drm: Move DRM_ROTATE bits out of omapdrm into drm_crtc.h

The rotation property stuff should be standardized among all drivers.
Move the bits to drm_crtc.h from omap_drv.h.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Acked-by: Dave Airlie <airlied@linux.ie>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>