cifs: set correct tcon status after initial tree connect

cifs_tcon::status wasn't correctly updated to TID_GOOD after initial
tree connect thus staying at TID_NEW as long as it was connected.

Cc: stable@vger.kernel.org
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>