buildroot: Update to 3585b4c

Jeremy Kerr (2):
      package/petitboot: Update init scripts for new pb-config utility
      package/kexec-lite: Add trampoline fix for LE

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
diff --git a/buildroot b/buildroot
index 047bf10..3585b4c 160000
--- a/buildroot
+++ b/buildroot
@@ -1 +1 @@
-Subproject commit 047bf10f5e0f2fe9115b911d448e8e0c955c0362
+Subproject commit 3585b4caef53cf6adb2d85571c38f83f7e6be6e6