scsi: ufs-msm: phy configuration to support rate B

This change adds phy configuration to support working in rate B
in case vendor power-mode preferences are pre-defined to work in
rate B.
Note: This change doesn't configure the default working rate
to be rate B, but only adds the support to do so.

Change-Id: Iec896917f9c76dcc3b5383c211871c7edf215b44
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>