rds: rds_message_zcopy_from_user() can be static

Fixes: d40a126b16ea ("rds: refactor zcopy code into rds_message_zcopy_from_user")
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/message.c

@@ -355,7 +355,7 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in
 	return rm;
 }
 
-int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter *from)
+static int rds_message_zcopy_from_user(struct rds_message *rm, struct iov_iter *from)
 {
 	unsigned long sg_off;
 	struct scatterlist *sg;