ASoC: SOF: core: Add missing error prints to device probe operation

Two error cases in snd_sof_device_probe() and sof_probe_continue() are
missing error prints.
If either of them happens it is not possible to identify the reason for the
failure.

Add dev_err() prints for the cases to aim debugging.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20210409220959.1543456-2-ranjani.sridharan@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/core.c

@@ -232,8 +232,11 @@ static int sof_probe_continue(struct snd_sof_dev *sdev)
 	}
 
 	ret = snd_sof_machine_register(sdev, plat_data);
-	if (ret < 0)
+	if (ret < 0) {
+		dev_err(sdev->dev,
+			"error: failed to register machine driver %d\n", ret);
 		goto fw_trace_err;
+	}
 
 	/*
 	 * Some platforms in SOF, ex: BYT, may not have their platform PM
@@ -309,8 +312,10 @@ int snd_sof_device_probe(struct device *dev, struct snd_sof_pdata *plat_data)
 	    !sof_ops(sdev)->block_read || !sof_ops(sdev)->block_write ||
 	    !sof_ops(sdev)->send_msg || !sof_ops(sdev)->load_firmware ||
 	    !sof_ops(sdev)->ipc_msg_data || !sof_ops(sdev)->ipc_pcm_params ||
-	    !sof_ops(sdev)->fw_ready)
+	    !sof_ops(sdev)->fw_ready) {
+		dev_err(dev, "error: missing mandatory ops\n");
 		return -EINVAL;
+	}
 
 	INIT_LIST_HEAD(&sdev->pcm_list);
 	INIT_LIST_HEAD(&sdev->kcontrol_list);