perf units: Move parse_tag_value() to units.[ch]

Its basically to do units handling, so move to a more appropriately
named object.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-90ob9vfepui24l8l2makhd9u@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/units.h b/tools/perf/util/units.h
index 3ed7774..f02c873 100644
--- a/tools/perf/util/units.h
+++ b/tools/perf/util/units.h
@@ -4,6 +4,13 @@
 #include <stddef.h>
 #include <linux/types.h>
 
+struct parse_tag {
+	char tag;
+	int  mult;
+};
+
+unsigned long parse_tag_value(const char *str, struct parse_tag *tags);
+
 unsigned long convert_unit(unsigned long value, char *unit);
 int unit_number__scnprintf(char *buf, size_t size, u64 n);