scsi: ufs: Add UFS host PHY driver for MSM targets

Add MSM UFS host PHY driver which binds with UFSHCD platform
driver exposing vendor specific operations to initialize the
PHY. Since the controller and PHY are tightly coupled in the
system, some of the MSM specific controller register
configuration is also applied inline while initializing PHY.

Add a new compatible property "qcom,ufshc" which specifies the
UFS host controller on MSM platforms. The UFS controller driver
binds with UFS PHY driver using the phandle reference of PHY
devicetree node.

Change-Id: If695a844d03268151c6c846bdfa6cee8ff84491b
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
[subhashj@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
[venkatg@codeaurora.org: resolved trivial merge conflicts]
Signed-off-by: Venkat Gopalakrishnan <venkatg@codeaurora.org>
[cang@codeaurora.org: Resolved trivial merge conflicts, dropped
all changes from ufs-msm.c]
Signed-off-by: Can Guo <cang@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>