msm: kgsl: Resolve conflicts in state changes

Only check requested state once, and fully transition to that
specific state.  This will resolve any conflicts arising from
changes to the requested_state as the state transition occurs.

Change-Id: I0836877d7d93d469158f7bfba5556fc082ebfe2a
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>