ASoC: pcm179x: Add I2C interface driver

The PCM179x family supports both SPI and I2C. This patch adds support
for the I2C interface.

Signed-off-by: Jacob Siverskog <jacob@teenage.engineering>
Reviewed-by: Johan Hovold <johan@kernel.org>
Acked-by: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index 56e94d8..9acd777 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -81,6 +81,7 @@
 snd-soc-nau8825-objs := nau8825.o
 snd-soc-pcm1681-objs := pcm1681.o
 snd-soc-pcm179x-codec-objs := pcm179x.o
+snd-soc-pcm179x-i2c-objs := pcm179x-i2c.o
 snd-soc-pcm179x-spi-objs := pcm179x-spi.o
 snd-soc-pcm3008-objs := pcm3008.o
 snd-soc-pcm3168a-objs := pcm3168a.o
@@ -286,6 +287,7 @@
 obj-$(CONFIG_SND_SOC_NAU8825)   += snd-soc-nau8825.o
 obj-$(CONFIG_SND_SOC_PCM1681)	+= snd-soc-pcm1681.o
 obj-$(CONFIG_SND_SOC_PCM179X)	+= snd-soc-pcm179x-codec.o
+obj-$(CONFIG_SND_SOC_PCM179X_I2C)	+= snd-soc-pcm179x-i2c.o
 obj-$(CONFIG_SND_SOC_PCM179X_SPI)	+= snd-soc-pcm179x-spi.o
 obj-$(CONFIG_SND_SOC_PCM3008)	+= snd-soc-pcm3008.o
 obj-$(CONFIG_SND_SOC_PCM3168A)	+= snd-soc-pcm3168a.o