scsi: libsas: Remove scsi_to_u32()

Since the function scsi_to_u32() is identical to get_unaligned_be32(),
change all scsi_to_u32() calls into get_unaligned_be32() calls.

Cc: Jian Luo <luojian5@huawei.com>
Cc: John Garry <john.garry@huawei.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>