ASoC: Intel: byt-rt5640: Remove IN2N pin from DAPM route table

I tested couple byt-rt5640 based platforms and they have single-ended
headset microphone connection to IN2P only. I guess IN2N was either defined
by accident or some early platform had floating ground for headset. It's
better to remove IN2N and add a custom route for such a platform if needed.
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/byt-rt5640.c

@@ -36,7 +36,6 @@ static const struct snd_soc_dapm_widget byt_rt5640_widgets[] = {
 static const struct snd_soc_dapm_route byt_rt5640_audio_map[] = {
 	{"Headset Mic", NULL, "MICBIAS1"},
 	{"IN2P", NULL, "Headset Mic"},
-	{"IN2N", NULL, "Headset Mic"},
 	{"DMIC1", NULL, "Internal Mic"},
 	{"Headphone", NULL, "HPOL"},
 	{"Headphone", NULL, "HPOR"},