net: l3mdev: Remove const from flowi6 arg to get_rt6_dst

Allow drivers to pass flow arg to functions where the arg is not const
and allow the driver to make updates as needed (eg., setting oif).

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c
index 7da9780..d90e4ef 100644
--- a/net/l3mdev/l3mdev.c
+++ b/net/l3mdev/l3mdev.c
@@ -108,7 +108,7 @@
  */
 
 struct dst_entry *l3mdev_get_rt6_dst(struct net *net,
-				     const struct flowi6 *fl6)
+				     struct flowi6 *fl6)
 {
 	struct dst_entry *dst = NULL;
 	struct net_device *dev;