sandbox: exynos: Move CONFIG_I2S_SAMSUNG to Kconfig

Move this over to Kconfig and tidy up.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/arndale_defconfig b/configs/arndale_defconfig
index 3c0a6b3..3d5c870 100644
--- a/configs/arndale_defconfig
+++ b/configs/arndale_defconfig
@@ -6,3 +6,4 @@
 CONFIG_SOUND=y
 CONFIG_CMD_SOUND=y
 CONFIG_I2S=y
+CONFIG_I2S_SAMSUNG=y
diff --git a/configs/smdk5250_defconfig b/configs/smdk5250_defconfig
index 58e0516..1234619 100644
--- a/configs/smdk5250_defconfig
+++ b/configs/smdk5250_defconfig
@@ -6,3 +6,4 @@
 CONFIG_SOUND=y
 CONFIG_CMD_SOUND=y
 CONFIG_I2S=y
+CONFIG_I2S_SAMSUNG=y
diff --git a/configs/snow_defconfig b/configs/snow_defconfig
index eb8c64a..d8c01e6 100644
--- a/configs/snow_defconfig
+++ b/configs/snow_defconfig
@@ -10,3 +10,4 @@
 CONFIG_SOUND=y
 CONFIG_CMD_SOUND=y
 CONFIG_I2S=y
+CONFIG_I2S_SAMSUNG=y
diff --git a/drivers/sound/Kconfig b/drivers/sound/Kconfig
index 759a10f..1b97af0 100644
--- a/drivers/sound/Kconfig
+++ b/drivers/sound/Kconfig
@@ -18,3 +18,13 @@
 	  SoC to the audio codec. This option enables sound support using
 	  I2S. It calls either of the two supported codecs (no use is made
 	  of driver model at present).
+
+config I2S_SAMSUNG
+	bool "Enable I2C support for Samsung SoCs"
+	depends on SOUND
+	help
+	  Samsung Exynos SoCs support an I2S interface for sending audio
+	  data to an audio codec. This option enables support for this,
+	  using one of the available audio codec drivers. Enabling this
+	  option provides an implementation for sound_init() and
+	  sound_play().
diff --git a/include/configs/exynos5250-common.h b/include/configs/exynos5250-common.h
index c9eac15..895d6e1 100644
--- a/include/configs/exynos5250-common.h
+++ b/include/configs/exynos5250-common.h
@@ -30,7 +30,6 @@
 
 /* Sound */
 #ifdef CONFIG_CMD_SOUND
-#define CONFIG_I2S_SAMSUNG
 #define CONFIG_SOUND_MAX98095
 #define CONFIG_SOUND_WM8994
 #endif