ASoC: twl6040: Move delayed_work struct inside twl6040_output for HS/HF

The delayed works for the output can be moved within the
twl6040_output struct (from the twl6040_data) to be better
organized.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>