scsi: qla2xxx: correctly shift host byte

The SCSI host byte has to be shifted by 16 not 6.

As Bart pointed out this patch does not change any functionality because
DID_OK == 0, but a wrong shift is irritating for the reviewer.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>