CIFS: Set ->should_dirty in cifs_user_readv()

The current code causes a static checker warning because ITER_IOVEC is
zero so the condition is never true.

Fixes: 6685c5e2 ("CIFS: Add asynchronous read support through kernel AIO")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/file.c

@@ -3271,7 +3271,7 @@ ssize_t cifs_user_readv(struct kiocb *iocb, struct iov_iter *to)
 	if (!is_sync_kiocb(iocb))
 		ctx->iocb = iocb;
 
-	if (to->type & ITER_IOVEC)
+	if (to->type == ITER_IOVEC)
 		ctx->should_dirty = true;
 
 	rc = setup_aio_ctx_iter(ctx, to, READ);