sandbox: exynos: Move CONFIG_SOUND_SANDBOX to Kconfig

Move this over to Kconfig and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>

configs/sandbox_defconfig

@@ -25,3 +25,4 @@ CONFIG_SPI_FLASH_SANDBOX=y
 CONFIG_TPM_TIS_SANDBOX=y
 CONFIG_SOUND=y
 CONFIG_CMD_SOUND=y
+CONFIG_SOUND_SANDBOX=y

drivers/sound/Kconfig

@@ -37,6 +37,15 @@ config SOUND_MAX98095
 	  audio data and I2C for codec control. At present it only works
 	  with the Samsung I2S driver.
 
+config SOUND_SANDBOX
+	bool "Support sandbox emulated audio codec"
+	depends on SANDBOX && SOUND
+	help
+	  U-Boot sandbox can emulate a sound device using SDL, playing the
+	  sound on the host machine. This option implements the sound_init()
+	  and sound_play() functions for sandbox. Note that you must install
+	  the SDL libraries for this to work.
+
 config SOUND_WM8994
 	bool "Support Wolfson Micro wm8994 audio codec"
 	depends on I2S_SAMSUNG

include/configs/sandbox.h

@@ -151,8 +151,6 @@
 
 #define CONFIG_BOARD_LATE_INIT
 
-#define CONFIG_SOUND_SANDBOX
-
 #ifndef SANDBOX_NO_SDL
 #define CONFIG_SANDBOX_SDL
 #endif