AFS: afs_send_empty_reply() doesn't require an iovec array

afs_send_empty_reply() doesn't require an iovec array with which to initialise
the msghdr, but can pass NULL instead.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>

fs/afs/rxrpc.c

@@ -770,15 +770,12 @@ static int afs_deliver_cm_op_id(struct afs_call *call, struct sk_buff *skb,
 void afs_send_empty_reply(struct afs_call *call)
 {
 	struct msghdr msg;
-	struct kvec iov[1];
 
 	_enter("");
 
-	iov[0].iov_base		= NULL;
-	iov[0].iov_len		= 0;
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, iov, 0, 0);	/* WTF? */
+	iov_iter_kvec(&msg.msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;