ftrace: Use LIST_HEAD to initialize clear_hash

Use LIST_HEAD() to initialize clear_hash instead of open-coding it.

Link: https://lore.kernel.org/linux-trace-kernel/20230809071551.913041-1-ruanjinjie@huawei.com

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Author: ruanjinjie-eng

kernel/trace/ftrace.c

@@ -7140,9 +7140,7 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
 	struct dyn_ftrace key;
 	struct ftrace_mod_map *mod_map = NULL;
 	struct ftrace_init_func *func, *func_next;
-	struct list_head clear_hash;
-
-	INIT_LIST_HEAD(&clear_hash);
+	LIST_HEAD(clear_hash);
 
 	key.ip = start;
 	key.flags = end;	/* overload flags, as it is unsigned long */