ASoC: SOF: reset enabled_cores state at suspend

The recent changes to use common code to power up/down DSP cores also
removed the reset of the core state at suspend. It turns out this is
still needed. When the firmware state is reset to
SOF_FW_BOOT_NOT_STARTED, also enabled_cores should be reset, and
existing DSP drivers depend on this.

BugLink: thesofproject#2824
Fixes: 42077f0 ("ASoC: SOF: update dsp core power status in common APIs")
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

sound/soc/sof/pm.c

@@ -256,6 +256,7 @@ static int sof_suspend(struct device *dev, bool runtime_suspend)
 
 	/* reset FW state */
 	sdev->fw_state = SOF_FW_BOOT_NOT_STARTED;
+	sdev->enabled_cores_mask = 0;
 
 	return ret;
 }