ASoC: Intel: sof_ssp_amp: 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/20230119163459.2235843-5-kai.vehmanen@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: plbossart

sound/soc/intel/boards/sof_ssp_amp.c

@@ -258,13 +258,12 @@ static struct snd_soc_dai_link *sof_card_dai_links_create(struct device *dev,
 		sof_rt1308_dai_link(&links[id]);
 	} else if (sof_ssp_amp_quirk & SOF_CS35L41_SPEAKER_AMP_PRESENT) {
 		cs35l41_set_dai_link(&links[id]);
-
-		/* feedback from amplifier */
-		links[id].dpcm_capture = 1;
 	}
 	links[id].platforms = platform_component;
 	links[id].num_platforms = ARRAY_SIZE(platform_component);
 	links[id].dpcm_playback = 1;
+	/* feedback from amplifier 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;