tracing/user_events: Fix memory leak in user_event_create()

Before current_user_event_group(), it has allocated memory and save it
in @name, this should freed before return error.

Link: https://lkml.kernel.org/r/20221115014445.158419-1-xiujianfeng@huawei.com

Fixes: e5d2718 ("tracing/user_events: Move pages/locks into groups to prepare for namespaces")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Beau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

kernel/trace/trace_events_user.c

@@ -1100,8 +1100,10 @@ static int user_event_create(const char *raw_command)
 
 	group = current_user_event_group();
 
-	if (!group)
+	if (!group) {
+		kfree(name);
 		return -ENOENT;
+	}
 
 	mutex_lock(&group->reg_mutex);