ASoC: Intel: sof_nau8825: always set dpcm_capture for amplifiers

The amplifier may provide hardware support for I/V feedback, or
alternatively the firmware may generate an echo reference attached to
the SSP and dailink used for the amplifier.

To avoid any issues with invalid/NULL substreams in the latter case,
always unconditionally set dpcm_capture.

Link: thesofproject#4083
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Péter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Link: https://lore.kernel.org/r/20230119163459.2235843-4-kai.vehmanen@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: plbossart

sound/soc/intel/boards/sof_nau8825.c

@@ -487,8 +487,6 @@ static struct snd_soc_dai_link *sof_card_dai_links_create(struct device *dev,
 			links[id].num_codecs = ARRAY_SIZE(max_98373_components);
 			links[id].init = max_98373_spk_codec_init;
 			links[id].ops = &max_98373_ops;
-			/* feedback stream */
-			links[id].dpcm_capture = 1;
 		} else if (sof_nau8825_quirk &
 				SOF_MAX98360A_SPEAKER_AMP_PRESENT) {
 			max_98360a_dai_link(&links[id]);
@@ -506,6 +504,9 @@ static struct snd_soc_dai_link *sof_card_dai_links_create(struct device *dev,
 		links[id].platforms = platform_component;
 		links[id].num_platforms = ARRAY_SIZE(platform_component);
 		links[id].dpcm_playback = 1;
+		/* feedback stream or firmware-generated echo reference */
+		links[id].dpcm_capture = 1;
+
 		links[id].no_pcm = 1;
 		links[id].cpus = &cpus[id];
 		links[id].num_cpus = 1;