scsi: ufs-msm: change default working mode in HS to rate A

So far, we used to work in the maximum HS (High Speed) rate available
by the UFS device (and supported by the controller) which is rate B.
This change changes the default working rate from rate B to rate A,
in order to gain more stability.

Change-Id: I797485b9699c5dab2a294b524f27c8e327b1e62d
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>