msm: kgsl: Disable unused GPU OPP for bus_devfreq

GPU HW supports multiple OPP but SW doesn't use all
of them always. SW uses only certain OPP based on
requirements or speed-bins. Because of this, in current
code, frequency table passed to devfreq_add_device as
part of bus_devfreq profile won't match the OPP table
added to same device if we have speed-bins, resulting
in incorrect min and max freq values on devfreq side.

This change disables OPP which SW doesn't use to make
sure frequency table and OPP table for bus_devfreq
matches.

Change-Id: I06d5ce16e17c95b1ab1254b2bd54c4c2efa89fe3
Signed-off-by: Deepak Kumar <dkumar@codeaurora.org>