Revert "msm: kgsl: Fix powerscale idle logic"

This reverts commit 3ea636d6026409524dad1919b7624d346e4f135f.
Revert "msm: kgsl: Add functions for enabling / disabling a powerscale policy"

This reverts commit 2ebaee82fe4cf64f3ae557272a1fdfcabf80c3d2.
Revert "msm: kgsl: Don't call through pwrscale functions when entering SLUMBER"

This reverts commit 2177abb3ed76c2aa46cc0da0cce2ed9d29714d35.