ipv4: export ip_flush_pending_frames

To avoid protocol modules implementing their own, export
ip_flush_pending_frames.
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: Tom Parkin <tparkin@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_output.c

@@ -1534,6 +1534,7 @@ void ip_flush_pending_frames(struct sock *sk)
 {
 	__ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
 }
+EXPORT_SYMBOL_GPL(ip_flush_pending_frames);
 
 struct sk_buff *ip_make_skb(struct sock *sk,
 			    struct flowi4 *fl4,