ASoC: rouleur-mbhc: Fix pop noise heard when headset insertion

Observed pop noise during impedance discharge after
headset/headphone plugged in.
Adding 40ms delay while discharge to complete ramp down properly.

Change-Id: I7eb4ba3423660454990722579b7c7b57156c8067
Signed-off-by: Vijay Kumar Maddula <quic_vmaddula@quicinc.com>