msm: pil: Unlock wakelock on proxy vote error path

If the proxy vote fails for some reason the wake lock will never
be released. Check the return value of the proxy vote and unlock
the wakelock if the proxy vote fails.

Change-Id: I0982896ab722bffed5f1c49247974dc84d5f3942
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>