drm/nouveau: 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: NEric Anholt <eric@anholt.net>
Reviewed-by: NEmil Velikov <emil.velikov@collabora.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: nouveau@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20190614203615.12639-24-daniel.vetter@ffwll.ch

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -1130,8 +1130,6 @@ driver_stub = {
 
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
-	.gem_prime_export = drm_gem_prime_export,
-	.gem_prime_import = drm_gem_prime_import,
 	.gem_prime_pin = nouveau_gem_prime_pin,
 	.gem_prime_res_obj = nouveau_gem_prime_res_obj,
 	.gem_prime_unpin = nouveau_gem_prime_unpin,