perf annotate: Introduce struct sym_hist_entry

struct sym_hist has addr[] but it should have not only number of samples
but also the sample period.  So use new struct symhist_entry to pave the
way to have that.

Committer notes:

This initial patch will only introduce the struct sym_hist_entry and use
only the nr_samples member, which makes the code clearer and paves the
way to save the period as well.

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1500500205-16553-1-git-send-email-treeze.taeung@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/ui/gtk/annotate.c b/tools/perf/ui/gtk/annotate.c
index 87e3760..d736fd5 100644
--- a/tools/perf/ui/gtk/annotate.c
+++ b/tools/perf/ui/gtk/annotate.c
@@ -34,10 +34,10 @@ static int perf_gtk__get_percent(char *buf, size_t size, struct symbol *sym,
 		return 0;
 
 	symhist = annotation__histogram(symbol__annotation(sym), evidx);
-	if (!symbol_conf.event_group && !symhist->addr[dl->offset])
+	if (!symbol_conf.event_group && !symhist->addr[dl->offset].nr_samples)
 		return 0;
 
-	percent = 100.0 * symhist->addr[dl->offset] / symhist->sum;
+	percent = 100.0 * symhist->addr[dl->offset].nr_samples / symhist->sum;
 
 	markup = perf_gtk__get_percent_color(percent);
 	if (markup)