perf ui progress: Make sure we always define step value

Unlikely, but we could have ui_progress__init being called with total <
16, which would set the next and step variables to 0. That would force
unnecessary ui_progress__ops->update calls because 'next' would never
raise.

Forcing the next and step values to be always > 0.

Signed-off-by: Jiri Olsa <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/ui/progress.c

···
 void ui_progress__init(struct ui_progress *p, u64 total, const char *title)
 {
 	p->curr = 0;
-	p->next = p->step = total / 16;
+	p->next = p->step = total / 16 ?: 1;
 	p->total = total;
 	p->title = title;