scsi: aacraid: Added sysfs for driver version

scsi: aacraid: Added sysfs for driver version

BugLink: http://bugs.launchpad.net/bugs/1668726
Added support to retrieve driver version from a new sysfs variable called
driver_version. It makes it easier for the user to figure out the driver
version that is currently running.

Signed-off-by: Raghava Aditya Renukunta <RaghavaAditya.Renukunta@microsemi.com>
Reviewed-by: David Carroll <David.Carroll@microsemi.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from linux-next commit 30202e067a81754cb78cb823b7ce7e7cddd040e2)
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>