ARM: dts: msm: Add pm-qos-latency to GPU dtsi for msm8916

Currently the code has a fixed CPU latency vote from
the GPU driver. Some targets have different latency
requirements to allow various low latency PC modes.
Allow the CPU latency vote to be programmable based
on target. 701us PM QOS allows the A7 targets select
Low Power Mode which is better in terms of power.
This will help save static leakage of A7 during
graphics use cases.

Change-Id: Iba706896663d88ac68321756b2e7ec48a33ea097
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>
Signed-off-by: Sunil Khatri <sunilkh@codeaurora.org>
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>