soundwire: bus: reset slave_notify status at each loop

soundwire: bus: reset slave_notify status at each loop

The code loops multiple times to deal with pending interrupts, but we
never reset the slave_notify status.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20201124013318.8963-3-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>