tracing: Remove unused __bad_type_size() method

__bad_type_size() is unused after
commit 04ae87a("ftrace: Rework event_create_dir()").
So, remove it.

Link: https://lkml.kernel.org/r/D062EC2E-7DB7-4402-A67E-33C3577F551E@gmail.com

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

kernel/trace/trace_syscalls.c

@@ -201,8 +201,6 @@ print_syscall_exit(struct trace_iterator *iter, int flags,
 	return trace_handle_return(s);
 }
 
-extern char *__bad_type_size(void);
-
 #define SYSCALL_FIELD(_type, _name) {					\
 	.type = #_type, .name = #_name,					\
 	.size = sizeof(_type), .align = __alignof__(_type),		\