SoC: soundwire: Add support to register for event listener

Add support to register/deregister for event listener to listen to
headset interrupt events during low power island mode.

Change-Id: I9d05261003ef9e4783e03b3acb529c864c07cbec
Signed-off-by: Sudheer Papothi <spapothi@codeaurora.org>