drm/vc4: Name the primary and cursor planes in fkms.

This makes debugging nicer, compared to trying to remember what the
IDs are.

Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/vc4/vc4_firmware_kms.c

@@ -267,7 +267,7 @@ static struct drm_plane *vc4_fkms_plane_init(struct drm_device *dev,
 	ret = drm_universal_plane_init(dev, plane, 0xff,
 				       &vc4_plane_funcs,
 				       primary ? &xrgb8888 : &argb8888, 1,
-				       type, NULL);
+				       type, primary ? "primary" : "cursor");
 
 	if (type == DRM_PLANE_TYPE_PRIMARY) {
 		vc4_plane->fbinfo =