scsi: ufs: Fix ufs power down/on specs violation

As per specs, while powering off/on the ufs device, RST_N signal and
REF_CLK signal should be between VSS(Ground) and VCCQ/VCCQ2.

Power down:
1. Assert RST_N low
2. Turn-off REF_CLK
3. Turn-off VCC
4. Turn-off VCCQ/VCCQ2.
power on:
1. Turn-on VCC
2. Turn-on VCCQ/VCCQ2
3. Turn-On REF_CLK
4. Deassert RST_N high.

Change-Id: I602e632d284a9d78431bf897558a4b8300ad3611
Signed-off-by: Ziqi Chen <ziqichen@codeaurora.org>