scsi: ufs-msm: add power management support

This patch adds the vendor specific UFS power management support for MSM
platform.

If UFS link hibernate operation is broken in HW, make sure that link
remains active and device in sleep state during the runtime suspend.
During system suspend, keep both link and device in power off state.

If UFS link hibernate operation is working properly in HW, keep the link
in hibernate state and device in sleep state during both runtime and
system suspend.

Change-Id: Ibc5be00eb9d5fd72ed116b887d835a12ed97ae78
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>