[ALSA] ASoC codecs: WM8731 support

This patch adds ASoC support for the WM8731 codec.
Supported features:-
 o Capture/Playback/Sidetone/Bypass.
 o 16 & 24 bit audio.
 o 8k - 96k sample rates.
 o DAPM.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/include/linux/i2c-id.h b/include/linux/i2c-id.h
index d38778f..01e98c2 100644
--- a/include/linux/i2c-id.h
+++ b/include/linux/i2c-id.h
@@ -115,6 +115,7 @@
 #define I2C_DRIVERID_KS0127	86	/* Samsung ks0127 video decoder */
 #define I2C_DRIVERID_TLV320AIC23B 87	/* TI TLV320AIC23B audio codec  */
 #define I2C_DRIVERID_ISL1208	88	/* Intersil ISL1208 RTC		*/
+#define I2C_DRIVERID_WM8731		89	/* Wolfson WM8731 audio codec */
 
 #define I2C_DRIVERID_I2CDEV	900
 #define I2C_DRIVERID_ARP        902    /* SMBus ARP Client              */