scsi: ufs: Porting UFS driver's changes from msm-4.14

This is a snapshot of the UFS driver taken as of msm-4.14 commit
<e6b78e34> ("scsi: ufs: fix bugs for UFS debugfs entry power_mode").
This change contains the UFS driver's changes for merging from kernel
version msm-4.14 to msm-4.19.

Change-Id: Ia99e4c46a6d1488f8ce5c065cd99a58542eaea35
Signed-off-by: Can Guo <cang@codeaurora.org>