cifs: Fix oops due to uncleared server->smbd_conn in reconnect
This is an automated ID intended to aid in discovery of potential security vulnerabilities. The actual impact and attack plausibility have not yet been proven. This ID is fixed in Linux Kernel version v5.15.91 by commit 4b83bc6f87eedab4599b0123e572a422689444be, it was introduced in version v4.16 by commit 8ef130f9ec27973f7b49e20c5a3b9134ca33026c. For more details please see the references link.