bpf: Copy comment about bpffs labelling into bpf_helpers.h

I found this comment in aosp/2103424 helpful in figuring out the correct
selinux domain for a newly added map.

Test: documentation only change
(cherry picked from https://android-review.googlesource.com/q/commit:dc66d3bb25fe4fbd4b74d6deea9de374e057bccd)
Merged-In: I96c06ff33605c8ed3f2ae6e8810bbcdc8e66b51b
Change-Id: I96c06ff33605c8ed3f2ae6e8810bbcdc8e66b51b
Bug: 283523051
1 file changed
tree: 29ab5f10fd25106ce1703014ca8ba30b69639d60
  1. client-libs/
  2. common/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING