ASoC: SOF: sof-audio: preserve topology filename override in nocodec mode

If the topology filename is modified at a higher level, be it with a
DMI quirk or a kernel module parameter, we don't want to use the
default 'nocodec' topology name extracted from descriptors.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Paul Olaru <paul.olaru@oss.nxp.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Link: https://lore.kernel.org/r/20220414184817.362215-8-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/sof-audio.c

@@ -652,7 +652,8 @@ int sof_machine_check(struct snd_sof_dev *sdev)
 		return -ENOMEM;
 
 	mach->drv_name = "sof-nocodec";
-	sof_pdata->tplg_filename = desc->nocodec_tplg_filename;
+	if (!sof_pdata->tplg_filename)
+		sof_pdata->tplg_filename = desc->nocodec_tplg_filename;
 
 	sof_pdata->machine = mach;
 	snd_sof_set_mach_params(mach, sdev);