aacraid: IOCTL pass-through command fix

The Linux aacriad driver fails to detect the case of SG list count=0 on IOCTL
pass-through command and cause intermittent fault.  The result is the Linux
aacriad driver send down IOCTL pass-through command with one not initialized
SG list to firmware when receiving SG list count =0 on pass-through command.

Signed-off-by: Mahesh Rajashekhara <Mahesh.Rajashekhara@pmcs.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Murthy Bhat <Murthy.Bhat@pmcs.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>