msm: kgsl: Refactor to support bus scaling in better way

Support bus scaling for both governor and
non-governor based targets. For the targets which
do not have governor support, gpu bus scaling is
done in kgsl.

This covers all possible cases with or without
separate ocmem scaling table, gpu axi scaling
and governor support.

Change-Id: Iee2d40c3cb3c41b1606a243c66a197d28f81de08
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>