Revert "cifs: reconnect work should have reference on server struct"

This reverts commit 19a4b9d6.

This earlier commit was making an assumption that each mod_delayed_work
called for the reconnect work would result in smb2_reconnect_server
being called twice. This assumption turns out to be untrue. So reverting
this change for now.

I will submit a follow-up patch to fix the actual problem in a different
way.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>