drm/meson: 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: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/1502034068-51384-3-git-send-email-noralf@tronnes.org

drivers/gpu/drm/meson/meson_drv.c

@@ -116,8 +116,6 @@ static struct drm_driver meson_driver = {
 
 	/* GEM Ops */
 	.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,