bpf: sync bpf.h uapi with tools/

This patch syncs tools/include/uapi/linux/bpf.h with the flow dissector
definitions from include/uapi/linux/bpf.h

Signed-off-by: Petar Penkov <ppenkov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>