drm/nouveau/kms/nv50-: Fix CRC-related compile errors with debugfs disabled

drm/nouveau/kms/nv50-: Fix CRC-related compile errors with debugfs disabled

Looks like I made the mistake of forgetting to check whether or not this
would build without CONFIG_DEBUG_FS, as the Kbuild bot reported some
issues building with tegra_defconfig:

In file included from drivers/gpu/drm/nouveau/nouveau_display.c:47:
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_head_crc_late_register’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:106:47: error: parameter name
omitted
  106 | static inline int nv50_head_crc_late_register(struct nv50_head *) {}
      |                                               ^~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h:106:54: warning: no return
statement in function returning non-void [-Wreturn-type]
  106 | static inline int nv50_head_crc_late_register(struct nv50_head *) {}
      |                                                      ^~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_handle_vblank’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:108:57: warning: ‘return’ with
a value, in function returning void [-Wreturn-type]
  108 | nv50_crc_handle_vblank(struct nv50_head *head) { return 0; }
      |                                                         ^
./drivers/gpu/drm/nouveau/dispnv50/crc.h:108:1: note: declared here
  108 | nv50_crc_handle_vblank(struct nv50_head *head) { return 0; }
      | ^~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_check’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:111:23: error: parameter name
omitted
  111 | nv50_crc_atomic_check(struct nv50_head *, struct nv50_head_atom *,
      |                       ^~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h:111:43: error: parameter name
omitted
  111 | nv50_crc_atomic_check(struct nv50_head *, struct nv50_head_atom *,
      |                                           ^~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h:112:9: error: parameter name
omitted
  112 |         struct nv50_head_atom *) {}
      |         ^~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h:112:16: warning: no return
statement in function returning non-void [-Wreturn-type]
  112 |         struct nv50_head_atom *) {}
      |                ^~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_stop_reporting’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:114:32: error: parameter name
omitted
  114 | nv50_crc_atomic_stop_reporting(struct drm_atomic_state *) {}
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_prepare_notifier_contexts’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:116:43: error: parameter name
omitted
  116 | nv50_crc_atomic_prepare_notifier_contexts(struct drm_atomic_state *) {}
      |                                           ^~~~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_start_reporting’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:118:33: error: parameter name
omitted
  118 | nv50_crc_atomic_start_reporting(struct drm_atomic_state *) {}
      |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_set’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:120:21: error: parameter name
omitted
  120 | nv50_crc_atomic_set(struct nv50_head *, struct nv50_head_atom *) {}
      |                     ^~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h:120:41: error: parameter name
omitted
  120 | nv50_crc_atomic_set(struct nv50_head *, struct nv50_head_atom *) {}
      |                                         ^~~~~~~~~~~~~~~~~~~~~~~
./drivers/gpu/drm/nouveau/dispnv50/crc.h: In function
‘nv50_crc_atomic_clr’:
./drivers/gpu/drm/nouveau/dispnv50/crc.h:122:21: error: parameter name
omitted
  122 | nv50_crc_atomic_clr(struct nv50_head *) {}
      |                     ^~~~~~~~~~~~~~~~~~
drivers/gpu/drm/nouveau/nouveau_display.c: In function
‘nouveau_framebuffer_new’:
drivers/gpu/drm/nouveau/nouveau_display.c:286:15: warning: variable
‘width’ set but not used [-Wunused-but-set-variable]
  286 |  unsigned int width, height, i;
      |               ^~~~~

So, fix the inline function declarations we use in
drm/drivers/gpu/drm/nouveau/dispnv50/crc.h when CONFIG_DEBUG_FS is
enabled.

Fixes: 12885ecbfe62 ("drm/nouveau/kms/nvd9-: Add CRC support")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>