ipv4: mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in some cases I placed the "fall through" comment
on its own line, which is what GCC is expecting to find.

Addresses-Coverity-ID: 115108
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 43a1bbe..ce4aa82 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -827,6 +827,7 @@ int inet_shutdown(struct socket *sock, int how)
 		err = -ENOTCONN;
 		/* Hack to wake up other listeners, who can poll for
 		   POLLHUP, even on eg. unconnected UDP sockets -- RR */
+		/* fall through */
 	default:
 		sk->sk_shutdown |= how;
 		if (sk->sk_prot->shutdown)
@@ -840,7 +841,7 @@ int inet_shutdown(struct socket *sock, int how)
 	case TCP_LISTEN:
 		if (!(how & RCV_SHUTDOWN))
 			break;
-		/* Fall through */
+		/* fall through */
 	case TCP_SYN_SENT:
 		err = sk->sk_prot->disconnect(sk, O_NONBLOCK);
 		sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;