ASoC: cs35l56: Prevent unbalanced pm_runtime in dsp_work() on SoundWire

ASoC: cs35l56: Prevent unbalanced pm_runtime in dsp_work() on SoundWire

Flush the SoundWire interrupt handler work instead of cancelling it.

When a SoundWire interrupt is triggered the pm_runtime is held
until the work has completed. It's therefore unsafe to cancel
the work, it must be flushed.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com
Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com
Link: https://lore.kernel.org/r/20230512144237.739000-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org