bpf: mark bpf_event_notify and bpf_event_init as static

Both of them are not declared in the headers and not used outside
of bpf_trace.c file.

Fixes: a38d1107 ("bpf: support raw tracepoints in modules")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

kernel/trace/bpf_trace.c

@@ -1297,7 +1297,8 @@ int bpf_get_perf_event_info(const struct perf_event *event, u32 *prog_id,
 }
 
 #ifdef CONFIG_MODULES
-int bpf_event_notify(struct notifier_block *nb, unsigned long op, void *module)
+static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
+			    void *module)
 {
 	struct bpf_trace_module *btm, *tmp;
 	struct module *mod = module;
@@ -1336,7 +1337,7 @@ static struct notifier_block bpf_module_nb = {
 	.notifier_call = bpf_event_notify,
 };
 
-int __init bpf_event_init(void)
+static int __init bpf_event_init(void)
 {
 	register_module_notifier(&bpf_module_nb);
 	return 0;