smb: client: fix missed ses refcounting

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix missed ses refcounting Use new cifs_smb_ses_inc_refcount() helper to get an active reference of @ses and @ses->dfs_root_ses (if set). This will prevent @ses->dfs_root_ses of being put in the next call to cifs_put_smb_ses() and thus potentially causing an use-after-free bug.