drm/prime: Ditch gem_prime_res_obj hook

Everyone is just using gem_object->resv now.

Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Link: https://patchwork.freedesktop.org/patch/msgid/20190725132655.11951-5-daniel.vetter@ffwll.ch

Documentation/gpu/todo.rst

@@ -196,15 +196,6 @@ Might be good to also have some igt testcases for this.
 
 Contact: Daniel Vetter, Noralf Tronnes
 
-Remove the ->gem_prime_res_obj callback
---------------------------------------------
-
-The ->gem_prime_res_obj callback can be removed from drivers by using the
-reservation_object in the drm_gem_object. It may also be possible to use the
-generic drm_gem_reservation_object_wait helper for waiting for a bo.
-
-Contact: Daniel Vetter
-
 idr_init_base()
 ---------------
 

drivers/gpu/drm/drm_prime.c

@@ -836,9 +836,6 @@ struct dma_buf *drm_gem_prime_export(struct drm_gem_object *obj,
 		.resv = obj->resv,
 	};
 
-	if (dev->driver->gem_prime_res_obj)
-		exp_info.resv = dev->driver->gem_prime_res_obj(obj);
-
 	return drm_gem_dmabuf_export(dev, &exp_info);
 }
 EXPORT_SYMBOL(drm_gem_prime_export);

include/drm/drm_drv.h

@@ -615,18 +615,6 @@ struct drm_driver {
 	 */
 	struct sg_table *(*gem_prime_get_sg_table)(struct drm_gem_object *obj);
 
-	/**
-	 * @gem_prime_res_obj:
-	 *
-	 * Optional hook to look up the &reservation_object for an buffer when
-	 * exporting it.
-	 *
-	 * FIXME: This hook is deprecated. Users of this hook should be replaced
-	 * by setting &drm_gem_object.resv instead.
-	 */
-	struct reservation_object * (*gem_prime_res_obj)(
-				struct drm_gem_object *obj);
-
 	/**
 	 * @gem_prime_import_sg_table:
 	 *