devicetree: bindings: scsi: HiSi SAS

Add devicetree bindings for HiSilicon SAS driver.

Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>