ASoC: qdsp6: q6apm-dai: only stop graphs that are started

ASoC: qdsp6: q6apm-dai: only stop graphs that are started

Its possible that the sound card is just opened and closed without actually
playing stream, ex: if the audio file itself is missing.

Even in such cases we do call stop on graphs that are not yet started.
DSP can throw errors in such cases, so add a check to see if the graph
was started before stopping it.

Fixes: 2a523038e301 ("ASoC: qdsp6: audioreach: add q6apm-dai support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220126113549.8853-5-srinivas.kandagatla@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>