scsi_dh_alua: sanitze sense code handling

scsi_dh_alua: sanitze sense code handling

The only check for a valid sense code is calling scsi_normalize_sense()
and check the return value. So drop the pointless checks and rely on
scsi_normalize_sense() to figure out if the sense code is valid.
With that we can also remove the 'senselen' field.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: Bart van Assche <bvanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
BugLink: http://bugs.launchpad.net/bugs/1567602
(cherry-picked from commit d3692a3d13e8ee2e371907d67d585d42297b4d66)
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>