ASoC: SOF: pcm: remove warning - initialize workqueue on open

If the SOF hw_params() fail, typically with an IPC error thrown by the
firmware, the period_elapsed workqueue is not initialized, but we
still cancel it in hw_free(), which results in a kernel warning.

Move the initialization to the .open callback. Tested on Broadwell
(Samus) and IceLake.

Fixes: e2803e61 ("ASoC: SOF: PCM: add period_elapsed work to fix
race condition in interrupt context")

GitHub issue: https://github.com/thesofproject/linux/issues/932Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/pcm.c

@@ -211,9 +211,6 @@ static int sof_pcm_hw_params(struct snd_pcm_substream *substream,
 	/* save pcm hw_params */
 	memcpy(&spcm->params[substream->stream], params, sizeof(*params));
 
-	INIT_WORK(&spcm->stream[substream->stream].period_elapsed_work,
-		  sof_pcm_period_elapsed_work);
-
 	/* clear hw_params_upon_resume flag */
 	spcm->hw_params_upon_resume[substream->stream] = 0;
 
@@ -432,6 +429,9 @@ static int sof_pcm_open(struct snd_pcm_substream *substream)
 	dev_dbg(sdev->dev, "pcm: open stream %d dir %d\n", spcm->pcm.pcm_id,
 		substream->stream);
 
+	INIT_WORK(&spcm->stream[substream->stream].period_elapsed_work,
+		  sof_pcm_period_elapsed_work);
+
 	caps = &spcm->pcm.caps[substream->stream];
 
 	ret = pm_runtime_get_sync(sdev->dev);