Merge pull request #2311 from shenki/buildroot-2018.05.2

buildroot: Merge 2018.05.2 stable release
diff --git a/buildroot b/buildroot
index 4f66fd5..1822255 160000
--- a/buildroot
+++ b/buildroot
@@ -1 +1 @@
-Subproject commit 4f66fd5bf4a8e64b9d39db0c74d07684bacda077
+Subproject commit 1822255eab2bb28bbd28713019110c429c9e1c35