staging: lustre: Fix sparse, using plain integer as NULL pointer in lov_object_fiemap()

Change 0 to NULL in lov_object_fiemap() in order to fix warning produced by
sparse
Signed-off-by: NAndrii Vladyka <tulup@mail.ru>
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/lov/lov_object.c

@@ -1335,7 +1335,7 @@ static int lov_object_fiemap(const struct lu_env *env, struct cl_object *obj,
 	int rc = 0;
 	int cur_stripe;
 	int stripe_count;
-	struct fiemap_state fs = { 0 };
+	struct fiemap_state fs = { NULL };
 
 	lsm = lov_lsm_addref(cl2lov(obj));
 	if (!lsm)