drm/udl: add support to export a handle to a FD on UDL.

Only importing an FD to a handle is currently supported on UDL,
but the exporting functionality is equally useful.

Signed-off-by: Haixia Shi <hshi@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 8607e9e..d5728ec 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -51,7 +51,9 @@
 	.dumb_destroy = drm_gem_dumb_destroy,
 	.fops = &udl_driver_fops,
 
+	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
+	.gem_prime_export = udl_gem_prime_export,
 	.gem_prime_import = udl_gem_prime_import,
 
 	.name = DRIVER_NAME,