ASoC: SOF: sof-audio: removed unused function

cppcheck warning:

sound/soc/sof/sof-audio.c:884:0: style: The function
'snd_sof_find_spcm_pcm_id' is never used. [unusedFunction]

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20220307181111.49392-5-ranjani.sridharan@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>