bpf, doc: improve sysctl knob description

Current context speaking of tcpdump filters is out of date these
days, so lets improve the sysctl description for the BPF knobs
a bit.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed