scsi: dt-bindings: ufs: Add HI3670 UFS controller binding

Add devicetree binding for HI3670 UFS controller. HI3760 SoC is very
similar to HI3660 SoC with almost same IPs. Only major difference in terms
of UFS is the PHY. HI3670 has 10nm PHY. But since the original driver
(HI3660 UFS) cannot make HI3670 UFS functional, a separate compatible
is added for HI3670 without any fallback.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Wei Li <liwei213@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>