drm: Add HDR capabilty field to plane structure

Hardware may have HDR capability on certain plane
engines. Enabling the same in drm plane structure
so that this can be communicated to user space.

Each drm driver should set this flag to true for planes
which support HDR.

Signed-off-by: Uma Shankar <uma.shankar@intel.com>

include/drm/drm_plane.h

@@ -515,6 +515,9 @@ struct drm_plane {
 
 	enum drm_plane_type type;
 
+	/* Value of true:1 means HDR is supported */
+	bool hdr_supported;
+
 	/**
 	 * @index: Position inside the mode_config.list, can be used as an array
 	 * index. It is invariant over the lifetime of the plane.