scsi: ufs-qcom: add support for platforms with bus scaling disabled

Some platforms do not enable the BUS_SCALING feature.
For such cases, we should wrap the routines that use this feature
with a configuration flag.

Change-Id: Iced5b6492a470eb5700b50a50de8260b6bb59753
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>