ls2080ardb: Convert to distro boot

Most new systems in U-Boot these days make use of the generic "distro"
framework which allows a user to have U-Boot scan for a bootable OS
on all available media types.

This patch extends the LS2080ARDB board to use that framework if the
hard coded NOR flash location does not contain a bootable image.

Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/Kconfig b/Kconfig
index 1263d0b..f3a9f73 100644
--- a/Kconfig
+++ b/Kconfig
@@ -56,6 +56,7 @@
 config DISTRO_DEFAULTS
 	bool "Select defaults suitable for booting general purpose Linux distributions"
 	default y if ARCH_SUNXI
+	default y if ARCH_LS2080A
 	default n
 	select CMD_BOOTZ if ARM && !ARM64
 	select CMD_BOOTI if ARM64