tools lib traceevent: Add mono clocks to be parsed in seconds

The mono clocks can display in seconds instead of whole numbers:

       trace-cmd-521   [001] 99176715281005: sched_waking:         comm=kworker/u16:2 pid=32118 prio=120 target_cpu=002
       trace-cmd-521   [001] 99176715286349: sched_wake_idle_without_ipi: cpu=2
       trace-cmd-521   [001] 99176715288047: sched_wakeup:         kworker/u16:2:32118 [120] success=1 CPU:002
       trace-cmd-521   [001] 99176715290022: sched_waking:         comm=trace-cmd pid=523 prio=120 target_cpu=000
       trace-cmd-521   [001] 99176715292332: sched_wake_idle_without_ipi: cpu=0
       trace-cmd-521   [001] 99176715292855: sched_wakeup:         trace-cmd:523 [120] success=1 CPU:000
       trace-cmd-521   [001] 99176715300697: sched_stat_runtime:   comm=trace-cmd pid=521 runtime=80233 [ns] vruntime=66705540554 [ns

Break it up in seconds:

       trace-cmd-521   [001] 99176.715281: sched_waking:         comm=kworker/u16:2 pid=32118 prio=120 target_cpu=002
       trace-cmd-521   [001] 99176.715286: sched_wake_idle_without_ipi: cpu=2
       trace-cmd-521   [001] 99176.715288: sched_wakeup:         kworker/u16:2:32118 [120] success=1 CPU:002
       trace-cmd-521   [001] 99176.715290: sched_waking:         comm=trace-cmd pid=523 prio=120 target_cpu=000
       trace-cmd-521   [001] 99176.715292: sched_wake_idle_without_ipi: cpu=0
       trace-cmd-521   [001] 99176.715293: sched_wakeup:         trace-cmd:523 [120] success=1 CPU:000
       trace-cmd-521   [001] 99176.715301: sched_stat_runtime:   comm=trace-cmd pid=521 runtime=80233 [ns] vruntime=66705540554 [ns]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Link: http://lkml.kernel.org/r/20190401164342.976554023@goodmis.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/event-parse.c

@@ -5445,7 +5445,8 @@ static bool is_timestamp_in_us(char *trace_clock, bool use_trace_clock)
 		return true;
 
 	if (!strcmp(trace_clock, "local") || !strcmp(trace_clock, "global")
-	    || !strcmp(trace_clock, "uptime") || !strcmp(trace_clock, "perf"))
+	    || !strcmp(trace_clock, "uptime") || !strcmp(trace_clock, "perf")
+	    || !strncmp(trace_clock, "mono", 4))
 		return true;
 
 	/* trace_clock is setting in tsc or counter mode */