[SCSI] Add Promise SuperTrak driver

[SCSI] Add Promise SuperTrak driver

Add Promise SuperTrak 'stex' driver, supporting SuperTrak
EX8350/8300/16350/16300 controllers.  The controller's firmware accepts
SCSI commands, handing them to the underlying RAID or JBOD disks.

The driver consisted of the following cleanups and fixes, beyond its
initial submission:

Ed Lin:
      stex: cleanup and minor fixes
      stex: add new device ids
      stex: update internal copy code path
      stex: add hard reset function
      stex: adjust command timeout in slave_config routine
      stex: use more efficient method for unload/shutdown flush

Jeff Garzik:
      [SCSI] Add Promise SuperTrak 'shasta' driver.
      Rename drivers/scsi/shasta.c to stex.c ("SuperTrak EX").
      [SCSI] stex: update with community comments from 'Promise SuperTrak' thread
      [SCSI] stex: Fix warning, trim trailing whitespace.
      [SCSI] stex: remove last remnants of "shasta" project code name
      [SCSI] stex: removed 6-byte command emulation
      [SCSI] stex: minor cleanups
      [SCSI] stex: minor fixes: irq flag, error return value
      [SCSI] stex: use dma_alloc_coherent()

Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>