perf list: Fix raw-dump arg

Ramkumar reported that perf list --raw-dump was broken by 44d742e.
Fix by making raw-dump a proper argument.

Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ramkumar Ramachandra <artagnon@gmail.com>