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/Kconfig b/sound/soc/codecs/Kconfig
index 13ae4fd..cceac73 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -2,6 +2,7 @@
 	tristate "Build all ASoC CODEC drivers"
 	depends on I2C
 	select SPI
+	select SPI_MASTER
 	select SND_SOC_AK4535
 	select SND_SOC_UDA1380
 	select SND_SOC_WM8510