[SCSI] stex: Fix for controller type st_yosemite

This is the fix for controller type st_yosemite, including
- max_lun is 256 (backward compatible)
- remove unneeded special handling of INQUIRY
- remove unnecessary listing of sub device ids

Signed-off-by: Ed Lin <ed.lin@promise.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>