drm: Add DRM_ROTATE_MASK and DRM_REFLECT_MASK

Makes it cleaner to separate the two from rotation variable.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

include/drm/drm_crtc.h

@@ -86,10 +86,12 @@ static inline uint64_t I642U64(int64_t val)
 }
 
 /* rotation property bits */
+#define DRM_ROTATE_MASK 0x0f
 #define DRM_ROTATE_0	0
 #define DRM_ROTATE_90	1
 #define DRM_ROTATE_180	2
 #define DRM_ROTATE_270	3
+#define DRM_REFLECT_MASK (~DRM_ROTATE_MASK)
 #define DRM_REFLECT_X	4
 #define DRM_REFLECT_Y	5