tracing: Remove unused __bad_type_size() method

__bad_type_size() is unused after
commit 04ae87a5

("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>