drm/rockchip: Drop drm_gem_prime_export/import

They're the default.

Aside: Would be really nice to switch the others over to
drm_gem_object_funcs.
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Link: https://patchwork.freedesktop.org/patch/msgid/20190614203615.12639-28-daniel.vetter@ffwll.ch

drivers/gpu/drm/rockchip/rockchip_drm_drv.c

@@ -219,8 +219,6 @@ static struct drm_driver rockchip_drm_driver = {
 	.dumb_create		= rockchip_gem_dumb_create,
 	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
-	.gem_prime_import	= drm_gem_prime_import,
-	.gem_prime_export	= drm_gem_prime_export,
 	.gem_prime_get_sg_table	= rockchip_gem_prime_get_sg_table,
 	.gem_prime_import_sg_table	= rockchip_gem_prime_import_sg_table,
 	.gem_prime_vmap		= rockchip_gem_prime_vmap,