[SCSI] esas2r: ATTO Technology ExpressSAS 6G SAS/SATA RAID Adapter Driver

This is a new driver for ATTO Technology's ExpressSAS series of hardware RAID
adapters.  It supports the following adapters:

    - ExpressSAS R60F
    - ExpressSAS R680
    - ExpressSAS R608
    - ExpressSAS R644

Signed-off-by: Bradley Grove <bgrove@attotech.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>