Merge pull request #3120 from shenki/buildroot-2019.05.2

buildroot: Update to 2019.05.2
diff --git a/buildroot b/buildroot
index aced055..3f377c0 160000
--- a/buildroot
+++ b/buildroot
@@ -1 +1 @@
-Subproject commit aced0552cc05842aa6ef5cf580afa52d9a871d80
+Subproject commit 3f377c067bff5c36ecd060300885d04db8f6971e