ALSA: ASoC: Add SPI support for WM8731

[Modified to allow runtime selection between I2C and SPI and to select
SPI_MASTER for all codecs build so this is included. -- broonie]

Signed-off-by: Cliff Cai <cliff.cai@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/soc/codecs/wm8731.h b/sound/soc/codecs/wm8731.h
index 0f81239..95190e9 100644
--- a/sound/soc/codecs/wm8731.h
+++ b/sound/soc/codecs/wm8731.h
@@ -35,6 +35,7 @@
 #define WM8731_DAI		0
 
 struct wm8731_setup_data {
+	int            spi;
 	int            i2c_bus;
 	unsigned short i2c_address;
 };