ASoC: SOF: Add FW state to debugfs

Allow system health detection mechanisms to check the FW state, this
will allow them to check if the FW is in its "crashed" state going
forward to help automatically diagnose driver state.

Signed-off-by: Curtis Malainey <cujomalainey@chromium.org>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20221220125629.8469-4-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/debug.c

@@ -353,7 +353,9 @@ int snd_sof_dbg_init(struct snd_sof_dev *sdev)
 			return err;
 	}
 
-	return 0;
+	return snd_sof_debugfs_buf_item(sdev, &sdev->fw_state,
+					sizeof(sdev->fw_state),
+					"fw_state", 0444);
 }
 EXPORT_SYMBOL_GPL(snd_sof_dbg_init);