dm: exynos: Move driver model CONFIGs to Kconfig

Remove driver model CONFIGs from the board config headers and use Kconfig
instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/cpu/armv7/exynos/Kconfig b/arch/arm/cpu/armv7/exynos/Kconfig
index 7fcb5d2..17ad567 100644
--- a/arch/arm/cpu/armv7/exynos/Kconfig
+++ b/arch/arm/cpu/armv7/exynos/Kconfig
@@ -65,6 +65,21 @@
 config SYS_SOC
 	default "exynos"
 
+config DM
+	default y if !SPL_BUILD
+
+config DM_SERIAL
+	default y if !SPL_BUILD
+
+config DM_SPI
+	default y if !SPL_BUILD
+
+config DM_SPI_FLASH
+	default y if !SPL_BUILD
+
+config DM_GPIO
+	default y if !SPL_BUILD
+
 source "board/samsung/smdkv310/Kconfig"
 source "board/samsung/trats/Kconfig"
 source "board/samsung/universal_c210/Kconfig"