[PATCH] perf/core: fix missing static inline on perf_cgroup_switch

["Ben Dooks (Codethink)" <ben.dooks@codethink.co.uk>]

It looks like a "static inline" has been missed in front
of the empty definition of perf_cgroup_switch under
certain configurations. Fixes the following sparse warning:

kernel/events/core.c:1035:1: warning: symbol 'perf_cgroup_switch' was not declared. Should it be static?

Signed-off-by: Ben Dooks (Codethink) <ben.dooks@codethink.co.uk>
---
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linux-kernel@vger.kernel.org
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index aec8dba2bea4..a4bad9f32fb7 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1031,7 +1031,7 @@ perf_cgroup_set_timestamp(struct task_struct *task,
 {
 }
 
-void
+static inline void
 perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
 {
 }
-- 
2.24.0.rc1