drm/fbdev-dma: remove obsolete kernel-doc references

drm/fbdev-dma: remove obsolete kernel-doc references

The kernel-doc comments in these 3 files was removed so remove the
references to these files to prevent kernel-doc warnings.

drivers/gpu/drm/drm_fbdev_dma.c:1: warning: no structured comments found
drivers/gpu/drm/drm_fbdev_shmem.c:1: warning: no structured comments found
drivers/gpu/drm/drm_fbdev_ttm.c:1: warning: no structured comments found

Fixes: 731fddf4302e ("drm/fbdev-dma: Remove obsolete setup function")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/all/20241002142250.07e1c46c@canb.auug.org.au/
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20241017024813.61908-1-rdunlap@infradead.org