drm: Reject stereo modes with an unknown layout

The kernel shouldn't accept invalid modes, just say No.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --cc drivers/gpu/drm/drm_crtc.c
Simple merge

diff --cc include/drm/drm_crtc.h
Simple merge

diff --cc include/uapi/drm/drm_mode.h
Simple merge