[SCSI] 3w-9xxx: add support for 9690SA

The attached patch updates the 3ware 9000 driver:

- Fix dma mask setting to fallback to 32-bit if 64-bit fails.
- Add support for 9690SA controllers.

Signed-off-by: Adam Radford <linuxraid@amcc.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>