ASoC: Intel: sof_sdw: add dailink .trigger callback

Add trigger functionality to dailink, so far only .startup() and
.shutdown() were implemented at the machine driver level.

The companion patch for this patch is the removal of the trigger
callback at the DAI level in drivers/soundwire/intel.c

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20200904182854.3944-3-yung-chuan.liao@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>