u-boot: Upgrade AST2400 machines to 2016.05 tree.

Move 2016.05 tree to point at the latest openbmc commit and point
all AST2400 machines to it.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/meta-ast2400/recipes-bsp/u-boot/u-boot_%.bbappend b/meta-ast2400/recipes-bsp/u-boot/u-boot_%.bbappend
new file mode 100644
index 0000000..ef6a709
--- /dev/null
+++ b/meta-ast2400/recipes-bsp/u-boot/u-boot_%.bbappend
@@ -0,0 +1,3 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
+
+SRC_URI += "file://fw_env.config"