drm/omap: check if rotation is supported before commit

omapdrm is missing a check on the validity of the rotation property.
This leads to omapdrm possibly trying to use rotation on non-rotateable
framebuffer, which causes the overlay setup to fail.

This patch adds the necessary check to omap_plane_atomic_check().

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
index c077367..16c3eee 100644
--- a/drivers/gpu/drm/omapdrm/omap_drv.h
+++ b/drivers/gpu/drm/omapdrm/omap_drv.h
@@ -189,6 +189,7 @@
 		struct omap_drm_window *win, struct omap_overlay_info *info);
 struct drm_connector *omap_framebuffer_get_next_connector(
 		struct drm_framebuffer *fb, struct drm_connector *from);
+bool omap_framebuffer_supports_rotation(struct drm_framebuffer *fb);
 
 void omap_gem_init(struct drm_device *dev);
 void omap_gem_deinit(struct drm_device *dev);