scsi: ufs-msm: avoid code duplication when setting timer register

since two different routines implement almost the same logic of
scanning the ufs clocks, getting the rate of "core_clk" and
setting a vendor timer register with a calculated value,
we should use only one routine to do that in order to minimize
potential errors

Change-Id: I22728295074acfbe4d421996ea9eaa1f29cb3a32
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>