Convert CONFIG_BOARD_TYPES to Kconfig

This converts the following to Kconfig:
   CONFIG_BOARD_TYPES

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Acked-by: Alexey Brodkin <abrodkin@synopsys.com>
Reviewed-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/configs/odroid-xu3_defconfig b/configs/odroid-xu3_defconfig
index 11796e5..f6f05b2 100644
--- a/configs/odroid-xu3_defconfig
+++ b/configs/odroid-xu3_defconfig
@@ -2,6 +2,7 @@
 CONFIG_ARCH_EXYNOS=y
 CONFIG_SYS_TEXT_BASE=0x43E00000
 CONFIG_ARCH_EXYNOS5=y
+CONFIG_BOARD_TYPES=y
 CONFIG_IDENT_STRING=" for ODROID-XU3/XU4/HC1/HC2"
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_NR_DRAM_BANKS=8