Sync with latest libbpf repo

Sync up to the following commit:
  22411acc4b2c ci: Add userfaultfd kernel config

Signed-off-by: Yonghong Song <yhs@fb.com>

diff --git a/src/cc/libbpf b/src/cc/libbpf
index 96268bf..22411ac 160000 (submodule)
--- a/src/cc/libbpf
+++ b/src/cc/libbpf
@@ -1 +1 @@
-Subproject commit 96268bf0c2b73b3ba91172a74179c2272870b8f8
+Subproject commit 22411acc4b2c846868fd570b2d9f3b016d2af2cb