add a comment about page size vs bpf ring buffer sizing am: 28f01bb027 am: cd4022ef2a am: 9045516e4a am: e5a0a70b78 am: bfb38761fd

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

Change-Id: Ia88378a72f6ed4ddd9ea392b435944eef019963d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>