sandbox: Add a simple sound driver

Add a sound driver for sandbox, which uses SDL.

Tested-by: Che-Liang Chiou <clchiou@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/sound/Makefile b/drivers/sound/Makefile
index 6d25292..3793f8a 100644
--- a/drivers/sound/Makefile
+++ b/drivers/sound/Makefile
@@ -7,5 +7,7 @@
 
 obj-$(CONFIG_SOUND)	+= sound.o
 obj-$(CONFIG_I2S)	+= samsung-i2s.o
+obj-$(CONFIG_I2S_SAMSUNG)	+= samsung-i2s.o
+obj-$(CONFIG_SOUND_SANDBOX)	+= sandbox.o
 obj-$(CONFIG_SOUND_WM8994)	+= wm8994.o
 obj-$(CONFIG_SOUND_MAX98095)	+= max98095.o