ASoC: wsa881x: cancel delayed work queue during device down

When device down is called, the work queue for temparature reading
should be cancelled. Without this, there might be read/write happening
while WSA881x device is still in down (no clock) state.

Change-Id: Ib0a6a9e5f8b45c3952e6a7fe5889901971bf0f08
Signed-off-by: Banajit Goswami <bgoswami@codeaurora.org>