snic: LUN goes offline due to scsi cmd timeouts

- LUN goes offline if there are at least two scsi command timeouts
  Completing the IO with scsi_done() fixes the issue.

Signed-off-by: Narsimhulu Musini <nmusini@cisco.com>
Signed-off-by: Sesidhar Baddela <sebaddel@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>