drm: Fix plane type uabi breakage

Turns out assuming that only stuff in uabi is uabi is a bit naive, and
we have a bunch of properties for which the enum values are placed in
random headers. A proper fix would be to split out uapi include
headers, but meanwhile sprinkle at least some warning over them.

Fixes: 532b36712ddf ("drm/doc: Polish for drm_plane.[hc]")
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1474612525-9488-1-git-send-email-daniel.vetter@ffwll.ch

include/drm/drm_blend.h

@@ -33,6 +33,9 @@ struct drm_atomic_state;
  * Rotation property bits. DRM_ROTATE_<degrees> rotates the image by the
  * specified amount in degrees in counter clockwise direction. DRM_REFLECT_X and
  * DRM_REFLECT_Y reflects the image along the specified axis prior to rotation
+ *
+ * WARNING: These defines are UABI since they're exposed in the rotation
+ * property.
  */
 #define DRM_ROTATE_0	BIT(0)
 #define DRM_ROTATE_90	BIT(1)

include/drm/drm_plane.h

@@ -333,8 +333,19 @@ struct drm_plane_funcs {
  * DRM_CLIENT_CAP_UNIVERSAL_PLANES client capability bit to indicate that they
  * wish to receive a universal plane list containing all plane types. See also
  * drm_for_each_legacy_plane().
+ *
+ * WARNING: The values of this enum is UABI since they're exposed in the "type"
+ * property.
  */
 enum drm_plane_type {
+	/**
+	 * @DRM_PLANE_TYPE_OVERLAY:
+	 *
+	 * Overlay planes represent all non-primary, non-cursor planes. Some
+	 * drivers refer to these types of planes as "sprites" internally.
+	 */
+	DRM_PLANE_TYPE_OVERLAY,
+
 	/**
 	 * @DRM_PLANE_TYPE_PRIMARY:
 	 *
@@ -353,14 +364,6 @@ enum drm_plane_type {
 	 * DRM_IOCTL_MODE_CURSOR2 IOCTLs.
 	 */
 	DRM_PLANE_TYPE_CURSOR,
-
-	/**
-	 * @DRM_PLANE_TYPE_OVERLAY:
-	 *
-	 * Overlay planes represent all non-primary, non-cursor planes. Some
-	 * drivers refer to these types of planes as "sprites" internally.
-	 */
-	DRM_PLANE_TYPE_OVERLAY,
 };