ASoC: Add max98090 codec driver

This patch adds the max98090 codec prototype driver.
It supports Headphone only at this point.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index b92759a..1801a65 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -44,6 +44,7 @@
 	select SND_SOC_LM4857 if I2C
 	select SND_SOC_LM49453 if I2C
 	select SND_SOC_MAX98088 if I2C
+	select SND_SOC_MAX98090 if I2C
 	select SND_SOC_MAX98095 if I2C
 	select SND_SOC_MAX9850 if I2C
 	select SND_SOC_MAX9768 if I2C
@@ -258,6 +259,9 @@
 config SND_SOC_MAX98088
        tristate
 
+config SND_SOC_MAX98090
+       tristate
+
 config SND_SOC_MAX98095
        tristate