ASoC: SOF: return -ENOTSUPP if D0I3 is not supported

No set_power_state ops means that the platform doesn't support D0i3,
return -ENOTSUPP for the case.
Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191025224122.7718-25-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/ops.h

@@ -199,7 +199,8 @@ static inline int snd_sof_dsp_set_power_state(struct snd_sof_dev *sdev,
 	if (sof_ops(sdev)->set_power_state)
 		return sof_ops(sdev)->set_power_state(sdev, substate);
 
-	return 0;
+	/* D0 substate is not supported */
+	return -ENOTSUPP;
 }
 
 /* debug */