configs/chiliboard: Bump U-Boot to 2018.03

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/grinn_chiliboard_defconfig

@@ -14,9 +14,8 @@ BR2_TARGET_ROOTFS_EXT2=y
 BR2_TARGET_ROOTFS_EXT2_4=y
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
-BR2_TARGET_UBOOT_CUSTOM_GIT=y
-BR2_TARGET_UBOOT_CUSTOM_REPO_URL="http://git.denx.de/u-boot.git"
-BR2_TARGET_UBOOT_CUSTOM_REPO_VERSION="aac477eca88dd81b18b48573ababee5112d571f3"
+BR2_TARGET_UBOOT_CUSTOM_VERSION=y
+BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2018.03"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="chiliboard"
 BR2_TARGET_UBOOT_FORMAT_IMG=y
 BR2_TARGET_UBOOT_FORMAT_CUSTOM=y