ait-plot-netperf-udp_stream: Remove milliseconds formatter

Leftover from copying from ait-plot (latrate).

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ait-plot-netperf-udp_stream: Remove the ymin/ymax calcs

Not really needed here.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
ait-plot-netperf-udp_stream: Invert the axes

By popular demand make msg_size the X axes and remote_throughput the Y
one.

Suggested-by: Jeremy Eder <jeder@redhat.com>
Suggested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>