perf tools: Explicitly declare inc_group_count as a void function

The return type is not defined, so it defaults to int, however, the
function is not returning anything, so this is clearly not correct. Make
it a void function.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1457008214-14393-1-git-send-email-colin.king@canonical.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

tools/perf/util/parse-events.y

@@ -28,7 +28,7 @@ do { \
 	INIT_LIST_HEAD(list);         \
 } while (0)
 
-static inc_group_count(struct list_head *list,
+static void inc_group_count(struct list_head *list,
 		       struct parse_events_evlist *data)
 {
 	/* Count groups only have more than 1 members */