tc: bpf: update list of archs with eBPF support in manpage

tc: bpf: update list of archs with eBPF support in manpage

Update the list of architectures supporting eBPF JIT as of Linux 4.18.
Also mention the Linux version where support for a particular
architecture was introduced. Finally, reformat the list of architectures
as a bullet list in order to make it more readable.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>