msm: kgsl: Create adreno power operations

This enables us to define target specific device power up/down
sequences. Also create adreno_power_cycle for certain settings
to take effect by powering down, change the settings and then
resume the device.

Change-Id: Ie6a0feb224f0b0babcd0249c812674c31dc6c4ab
Signed-off-by: Harshdeep Dhatt <hdhatt@codeaurora.org>