scsi: ufs: ufs-unisoc: Add support for Unisoc UFS host controller

Add driver code for Unisoc UFS host controller, along with UFS
initialization.

Signed-off-by: Zhe Wang <zhe.wang1@unisoc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>