ASoC: SOF: allow soundwire use desc->default_fw_filename

The old code always uses sof_fw_filename in struct snd_soc_acpi_mach
as the firmware name. However, firmware name should depend on the platform
instead of the machine. For example, different machines may use the same
soundwire link topology, but they are using the different firmware. In this
case, it's hard to determine in struct snd_soc_acpi_mach which firmware it
should use.
Signed-off-by: Libin Yang <libin.yang@intel.com>
Reviewed-by: Bard Liao <bard.liao@intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Tested-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20210125070500.807474-1-kai.vehmanen@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/intel/hda.c

@@ -1173,7 +1173,10 @@ static int hda_sdw_machine_select(struct snd_sof_dev *sdev)
 			mach->mach_params.links = mach->links;
 			mach->mach_params.link_mask = mach->link_mask;
 			mach->mach_params.platform = dev_name(sdev->dev);
-			pdata->fw_filename = mach->sof_fw_filename;
+			if (mach->sof_fw_filename)
+				pdata->fw_filename = mach->sof_fw_filename;
+			else
+				pdata->fw_filename = pdata->desc->default_fw_filename;
 			pdata->tplg_filename = mach->sof_tplg_filename;
 		} else {
 			dev_info(sdev->dev,