msm: pil-q6v4: Move to common proxy voting

Remove the boiler plate workqueue and proxy voting code and move
to the common proxy infrastructure that the core pil code
provides. This has the added benefit of fixing any issues where
suspend happens before the proxy vote is removed.

Change-Id: I7645b9297a0811e848a780e8963de204104b3997
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>