drm/sun4i: tv: Include drm_atomic.h

drm/sun4i: tv: Include drm_atomic.h

Commit ec491291dc94 ("drm/sun4i: tv: Merge mode_set into atomic_enable")
has introduced a call to drm_atomic_get_new_crtc_state(), but didn't
include drm_atomic.h.

On CONFIG_OF systems, this is fine because drm_atomic.h is included by
drm_of.h through drm_bridge.h. However, whenever CONFIG_OF isn't set, we
end up with a compilation error.

Fixes: ec491291dc94 ("drm/sun4i: tv: Merge mode_set into atomic_enable")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220909093116.4141982-1-maxime@cerno.tech