ASoC: Intel: kbl_rt5663_max98927: Map BTN_0 to KEY_PLAYPAUSE

The Android 3.5mm Headset jack specification mentions that BTN_0 should
be mapped to KEY_MEDIA, but this is less logical than KEY_PLAYPAUSE,
which has much broader userspace support.

For example, the Chrome OS userspace now supports KEY_PLAYPAUSE to toggle
play/pause of videos and audio, but does not handle KEY_MEDIA.

Furthermore, Android itself now supports KEY_PLAYPAUSE equivalently, as the
new USB headset spec requires KEY_PLAYPAUSE for BTN_0.
https://source.android.com/devices/accessories/headset/usb-headset-spec

Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/boards/kbl_rt5663_max98927.c

@@ -225,7 +225,7 @@ static int kabylake_rt5663_codec_init(struct snd_soc_pcm_runtime *rtd)
 	}
 
 	jack = &ctx->kabylake_headset;
-	snd_jack_set_key(jack->jack, SND_JACK_BTN_0, KEY_MEDIA);
+	snd_jack_set_key(jack->jack, SND_JACK_BTN_0, KEY_PLAYPAUSE);
 	snd_jack_set_key(jack->jack, SND_JACK_BTN_1, KEY_VOICECOMMAND);
 	snd_jack_set_key(jack->jack, SND_JACK_BTN_2, KEY_VOLUMEUP);
 	snd_jack_set_key(jack->jack, SND_JACK_BTN_3, KEY_VOLUMEDOWN);