dsp: Reset core hw vote client handle in SSR

Reset core hw vote client handle in SSR use cases
and do not unvote when the client handle is 0.
This is to clean up the client ids in SSR in
order to avoid unusual client deregistrations.

Change-Id: Id0cee50f7ca27e29db6134b7a70ae75334e0d765
Signed-off-by: Aditya Bavanari <abavanar@codeaurora.org>