ASoC: SOF: ipc4-topology: Protect pipeline free with mutex

ASoC: SOF: ipc4-topology: Protect pipeline free with mutex

When starting/stopping multiple streams in parallel, pipeline triggers
and pipeline frees can get interleaved. So use the same mutex used for
pipeline trigger to protect the pipeline frees as well. Rename the
trigger_mutex to pipeline_state_mutex for more clarity.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20230127120031.10709-16-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>