ASoC: rt286: Make RT286_SET_GPIO_* readable and writable

The GPIO configuration cannot be applied if the registers are inaccessible.
This prevented the headset mic from working on the Dell XPS 13 9343.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=114171
Signed-off-by: David Ward <david.ward@gatech.edu>
Link: https://lore.kernel.org/r/20210418134658.4333-5-david.ward@gatech.edu
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt286.c

@@ -171,6 +171,9 @@ static bool rt286_readable_register(struct device *dev, unsigned int reg)
 	case RT286_PROC_COEF:
 	case RT286_SET_AMP_GAIN_ADC_IN1:
 	case RT286_SET_AMP_GAIN_ADC_IN2:
+	case RT286_SET_GPIO_MASK:
+	case RT286_SET_GPIO_DIRECTION:
+	case RT286_SET_GPIO_DATA:
 	case RT286_SET_POWER(RT286_DAC_OUT1):
 	case RT286_SET_POWER(RT286_DAC_OUT2):
 	case RT286_SET_POWER(RT286_ADC_IN1):