ASoC: wcd937x: Fix mbhc insertion interrupt not cleared issue on wcd937x

wcd937x interrupt uses regmap irq framework which needs
to clear mbhc interrupt by setting clear_ack bit.
Enable this bit to clear interrupt.

Change-Id: I138ca7eda5da1b77e366797f4b81191d9b851a03
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>