ASoC: SOF: topology: remove useless code

ASoC: SOF: topology: remove useless code

The patch "ASoC: SOF: Intel: hda: assign link DMA channel at run-time"
fixed the sof_link_hda_unload() to remove the call to the BE
hw_free op but left the rest of code that become redundant.

So, remove sof_link_hda_unload() along with the link_unload() op
entirely as it is not longer needed.

Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20210409220522.1542865-1-ranjani.sridharan@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>