epoll: Tiny cleanup to udp_sock_handler()

Move the test for c->no_udp into the function itself, rather than in the
dispatching switch statement to better localize the UDP specific logic, and
make for greated consistency with other handler functions.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

udp.c

@@ -756,7 +756,7 @@ void udp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
 	struct mmsghdr *mmh_recv;
 	int i, m;
 
-	if (!(events & EPOLLIN))
+	if (c->no_udp || !(events & EPOLLIN))
 		return;
 
 	if (v6) {