ftrace: Remove unused ftrace_force_update()

ftrace_force_update() is committed by Commit e1c08bd ("ftrace: force
recording") and removed by Commit cb7be3b ("ftrace: remove daemon").
Remove it in header file.

Link: https://lkml.kernel.org/r/1612409671-8249-1-git-send-email-hejinyang@loongson.cn

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

include/linux/ftrace.h

@@ -485,7 +485,6 @@ struct dyn_ftrace {
 	struct dyn_arch_ftrace	arch;
 };
 
-int ftrace_force_update(void);
 int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
 			 int remove, int reset);
 int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
@@ -740,7 +739,6 @@ extern void ftrace_disable_daemon(void);
 extern void ftrace_enable_daemon(void);
 #else /* CONFIG_DYNAMIC_FTRACE */
 static inline int skip_trace(unsigned long ip) { return 0; }
-static inline int ftrace_force_update(void) { return 0; }
 static inline void ftrace_disable_daemon(void) { }
 static inline void ftrace_enable_daemon(void) { }
 static inline void ftrace_module_init(struct module *mod) { }