nfsd: allow configuring nfsd to listen on 5-digit ports

Note a 16-bit value can require up to 5 digits.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfsctl.c

@@ -712,7 +712,7 @@ static ssize_t __write_ports_addxprt(char *buf)
 	int port, err;
 	struct net *net = &init_net;
 
-	if (sscanf(buf, "%15s %4u", transport, &port) != 2)
+	if (sscanf(buf, "%15s %5u", transport, &port) != 2)
 		return -EINVAL;
 
 	if (port < 1 || port > USHRT_MAX)