[SCSI] stex: small code fixes and changes

These are some small code fixes and changes, including:
- use 64 bit when possible
- remove some unnecessary code (in interrupt, queuecommand routine etc.)
- code change for reset handler

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