cifs: Fix xid leak in cifs_create()

If the cifs already shutdown, we should free the xid before return,
otherwise, the xid will be leaked.

Fixes: 087f757b ("cifs: add shutdown support")
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Zhang Xiaoxu <zhangxiaoxu5@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>