drm/pl111: Use .dumb_map_offset and .dumb_destroy defaults

This driver can use the drm_driver.dumb_destroy and
drm_driver.dumb_map_offset defaults, so no need to set them.

Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: NNoralf Trønnes <noralf@tronnes.org>
Reviewed-by: NEric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/1500837417-40580-13-git-send-email-noralf@tronnes.org

drivers/gpu/drm/pl111/pl111_drv.c

@@ -159,8 +159,6 @@ static struct drm_driver pl111_drm_driver = {
 	.minor = 0,
 	.patchlevel = 0,
 	.dumb_create = drm_gem_cma_dumb_create,
-	.dumb_destroy = drm_gem_dumb_destroy,
-	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
 	.gem_free_object_unlocked = drm_gem_cma_free_object,
 	.gem_vm_ops = &drm_gem_cma_vm_ops,