cifs: On cifs_reconnect, resolve the hostname again.

On cifs_reconnect, make sure that DNS resolution happens again.
It could be the cause of connection to go dead in the first place.

This also contains the fix for a build issue identified by Intel bot.
Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: <stable@vger.kernel.org> # 5.11+
Signed-off-by: Steve French <stfrench@microsoft.com>