ASoC: dapm: use component prefix when checking widget names

On a TigerLake SoundWire platform, we see these warnings:

[   27.360086] rt5682 sdw:0:25d:5682:0: ASoC: DAPM unknown pin MICBIAS
[   27.360092] rt5682 sdw:0:25d:5682:0: ASoC: DAPM unknown pin Vref2

This is root-caused to the addition of a component prefix in the
machine driver. The tests in soc-dapm should account for a prefix
instead of reporting an invalid issue.
Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@linux.intel.com>
Signed-off-by: Shuming Fan <shumingf@realtek.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210208234043.59750-2-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-dapm.c

@@ -2528,9 +2528,20 @@ static struct snd_soc_dapm_widget *dapm_find_widget(
 {
 	struct snd_soc_dapm_widget *w;
 	struct snd_soc_dapm_widget *fallback = NULL;
+	char prefixed_pin[80];
+	const char *pin_name;
+	const char *prefix = soc_dapm_prefix(dapm);
+
+	if (prefix) {
+		snprintf(prefixed_pin, sizeof(prefixed_pin), "%s %s",
+			 prefix, pin);
+		pin_name = prefixed_pin;
+	} else {
+		pin_name = pin;
+	}
 
 	for_each_card_widgets(dapm->card, w) {
-		if (!strcmp(w->name, pin)) {
+		if (!strcmp(w->name, pin_name)) {
 			if (w->dapm == dapm)
 				return w;
 			else