asoc: mbhc: ignore mbhc event report during ssr

When ssr is in progress, during some race conditions
mbhc events are getting reported when codec is still
coming up. Ignore such events without reporting.

Change-Id: I3d3f78f97c2b855fc36a480f38c166bda2d979f0
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>