khadas-edge2: fix uboot

Author: efectn

config/boards/khadas-edge2.conf

@@ -33,7 +33,7 @@ function post_family_config__uboot_kedge2() {
 	display_alert "$BOARD" "Configuring ($BOARD) u-boot" "info"
 
 	declare -g BOOTSOURCE='https://github.com/khadas/u-boot.git'
-	declare -g BOOTBRANCH='branch:khadas-edges-v2017.09'
+	declare -g BOOTBRANCH="commit:df276095a29a02f8e7ce4f451770c06486106594"
 	declare -g BOOTPATCHDIR="legacy/u-boot-khadas-edge2-rk3588"
 	declare -g BOOTCONFIG="khadas-edge2-rk3588s_defconfig"
 	declare -g SRC_EXTLINUX="yes" # For now, use extlinux. Thanks Monka