[TCP]: Remove unneeded implicit type cast when calling tcp_minshall_update()

The tcp_minshall_update() function is called in exactly one place, and is
passed an unsigned integer for the mss_len argument.  Make the sign of the
argument match the sign of the passed variable in order to eliminate an
unneeded implicit type cast and a mixed sign comparison in
tcp_minshall_update().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tcp.h

@@ -803,7 +803,7 @@ static inline int tcp_is_cwnd_limited(const struct sock *sk, u32 in_flight)
 		return left <= tcp_max_burst(tp);
 }
 
-static inline void tcp_minshall_update(struct tcp_sock *tp, int mss,
+static inline void tcp_minshall_update(struct tcp_sock *tp, unsigned int mss,
 				       const struct sk_buff *skb)
 {
 	if (skb->len < mss)