dm: Kconfig: Move CONFIG_SYS_MALLOC_F_LEN to Kconfig

Move this option to Kconfig and update all boards.
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 17ad567..2064efa 100644
--- a/arch/arm/cpu/armv7/exynos/Kconfig
+++ b/arch/arm/cpu/armv7/exynos/Kconfig
@@ -80,6 +80,12 @@
 config DM_GPIO
 	default y if !SPL_BUILD
 
+config SYS_MALLOC_F
+	default y if !SPL_BUILD
+
+config SYS_MALLOC_F_LEN
+	default 0x400 if !SPL_BUILD
+
 source "board/samsung/smdkv310/Kconfig"
 source "board/samsung/trats/Kconfig"
 source "board/samsung/universal_c210/Kconfig"