drm: apple: Add .get_scanout_buffer for drm_panic support

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/apple_drv.c

@@ -119,6 +119,7 @@ static void apple_plane_atomic_update(struct drm_plane *plane,
 static const struct drm_plane_helper_funcs apple_plane_helper_funcs = {
 	.atomic_check	= apple_plane_atomic_check,
 	.atomic_update	= apple_plane_atomic_update,
+	.get_scanout_buffer = drm_fb_dma_get_scanout_buffer,
 };
 
 static void apple_plane_cleanup(struct drm_plane *plane)