Enable detecting of SCSI bus in mpt module.

Some servers does not have MPT-enabled controller attached to SCSI-0 and
calling mpt-status without any arguments fails. So we firsts recognize
the id where the controller is attached and then call status with the
right id.
Merge pull request #36 from JiriHorky/master

Enable detecting of SCSI id bus in mpt-status (#36)