msm: kgsl: Add support for peak power detection

A430 has capability to detect peak currect conditions and trigger
GPU clock throttling. Add support for peak power detection(PPD)
in the A430 feature list and program the registers at device start.

Change-Id: Iabfbbfa7a7c11b28510c18ad6c9e2641be958334
Signed-off-by: Suman Tatiraju <sumant@codeaurora.org>