perf pmu: Change convert_scale from static to global

The function convert_scale() can be used to convert string to unit and
scale. For example,

  s = "6000000000ns";
  convert_scale(s, &unit, &scale);

unit = "ns", scale = 6000000000.

Currently this function is static. This patch renames the function to
perf_pmu__convert_scale and changes the function to global.  No
functional change.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20190828055932.8269-2-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -102,7 +102,7 @@ static int pmu_format(const char *name, struct list_head *format)
 	return 0;
 }
 
-static int convert_scale(const char *scale, char **end, double *sval)
+int perf_pmu__convert_scale(const char *scale, char **end, double *sval)
 {
 	char *lc;
 	int ret = 0;
@@ -165,7 +165,7 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char *
 	else
 		scale[sret] = '\0';
 
-	ret = convert_scale(scale, NULL, &alias->scale);
+	ret = perf_pmu__convert_scale(scale, NULL, &alias->scale);
 error:
 	close(fd);
 	return ret;
@@ -373,7 +373,7 @@ static int __perf_pmu__new_alias(struct list_head *list, char *dir, char *name,
 				desc ? strdup(desc) : NULL;
 	alias->topic = topic ? strdup(topic) : NULL;
 	if (unit) {
-		if (convert_scale(unit, &unit, &alias->scale) < 0)
+		if (perf_pmu__convert_scale(unit, &unit, &alias->scale) < 0)
 			return -1;
 		snprintf(alias->unit, sizeof(alias->unit), "%s", unit);
 	}

tools/perf/util/pmu.h

@@ -96,4 +96,6 @@ struct perf_event_attr *perf_pmu__get_default_config(struct perf_pmu *pmu);
 
 struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu);
 
+int perf_pmu__convert_scale(const char *scale, char **end, double *sval);
+
 #endif /* __PMU_H */