add a comment about page size vs bpf ring buffer sizing am: 28f01bb027 am: cd4022ef2a am: 9045516e4a am: e5a0a70b78

Original change: https://android-review.googlesource.com/c/platform/system/bpf/+/2631549

Change-Id: I0ddd683e98133e61a0105595aceb94c7411e1b31
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>