ASoC: wcd-mbhc: Add support for unloading mbhc

Add lock and unlock for mbhc resource lock while
calling wcd_cancel_hs_detect_plug to avoid kernel
warning messages from deinit function.

CRs-fixed: 2039099
Change-Id: I732163fae68bc675e72142b3287d11a0c21f7375
Signed-off-by: Karthikeyan Mani <kmani@codeaurora.org>