BpfMap.java - add requires S+ annotation

Since the first mainline eBPF code (for Tethering offload)
landed in Android S.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ifb44a43a98e7f0ff4cd59017b47f64eff30ee715
2 files changed