ARM: dts: msm: Enable BIMC based GPU bus BW governor for MSM8939

Use generic BIMC governor infrastructure to activate GPU bus
bandwidth governor.
This enables dynamic AB bus voting from GPU.

Change-Id: I17dfe1c14476888e6de5c8cb7538b49b3ef16692
Signed-off-by: Mihir Patel <mihirp@codeaurora.org>