scsi: ufs-qcom: Remove unused MSM bus scaling APIs

MSM bus scaling has moved on to use interconnect framework and downstream
bus scaling APIs like msm_bus_scale*() do not exist anymore in the
kernel. Currently they are guarded by a config which also does not exist
and hence there are no build failures reported. Remove these unused
interfaces as they are currently no-ops and the scaling support that may be
added in future will use interconnect API.

Link: https://lore.kernel.org/r/20200804161033.15586-1-saiprakash.ranjan@codeaurora.org


Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>