CIFS: Add match_port check during looking for an existing connection (try #4)

If we have a share mounted by non-standard port and try to mount another share
on the same host with standard port, we connect to the first share again -
that's wrong. This patch fixes this bug.

Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Steve French <sfrench@us.ibm.com>