drm/msm/adreno: Add power management functions for system sleep

When a msm8016 based system is woken up from suspend, the firmware in
the adreno device hangs.

[   83.903416] qcom-iommu-ctx 1f09000.iommu-ctx: Unhandled context fault: fsr=0x202, iova=0x0000000000000000, fsynr=0x2, cb=1
[   85.853633] msm 1a00000.mdss: A306: hangcheck detected gpu lockup rb 0!
[   85.853661] msm 1a00000.mdss: A306:     completed fence: 370
[   85.859073] msm 1a00000.mdss: A306:     submitted fence: 372
[   85.865113] msm 1a00000.mdss: A306: hangcheck recover!

Fix this by adding pm_runtime_force_suspend/pm_runtime_force_resume
as sleep ops.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>