msm: kgsl: Add intermediate power levels

Make use of the two independent power domains to
add intermediate levels.  Attempt to just increase
the bus frequency before also raising the GPU
frequency.

Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>

Conflicts:
	arch/arm/boot/dts/msm8974-gpu.dtsi
	arch/arm/boot/dts/msm8974-v2.dtsi
	drivers/gpu/msm/kgsl_pwrctrl.c
	drivers/gpu/msm/kgsl_pwrctrl.h

Change-Id: Ibe85d1c02941430c5da83a75a09d5bc0ec5f8ec0