[ALSA] ASoC codecs: build files

This patch adds an ASoC Makefile and Kconfig for the WM8731, WM8750 and
WM9712 codecs.

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/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
new file mode 100644
index 0000000..3249a6e
--- /dev/null
+++ b/sound/soc/codecs/Makefile
@@ -0,0 +1,9 @@
+snd-soc-ac97-objs := ac97.o
+snd-soc-wm8731-objs := wm8731.o
+snd-soc-wm8750-objs := wm8750.o
+snd-soc-wm9712-objs := wm9712.o
+
+obj-$(CONFIG_SND_SOC_AC97_CODEC)	+= snd-soc-ac97.o
+obj-$(CONFIG_SND_SOC_WM8731)	+= snd-soc-wm8731.o
+obj-$(CONFIG_SND_SOC_WM8750)	+= snd-soc-wm8750.o
+obj-$(CONFIG_SND_SOC_WM9712)	+= snd-soc-wm9712.o