msm: kgsl: Move setstate functionality to adreno driver side

With multiple ringbuffers the current pagetable and active context
that is active on a ringbuffer can be different. Let the adreno
code handle the logic of maintaining the pagetable for a ringbuffer
and move the current active context to the ringbuffer structure to
facilitate this.

Change-Id: I092a758b089fd4877525542540dbd03f9770362c
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>