ftrace: Remove unused nr_trampolines var

It's not needed & not used since introducing old_hash: commit fef5aeeee9
("ftrace: Replace tramp_hash with old_*_hash to save space").

Link: http://lkml.kernel.org/r/1452699598-27610-1-git-send-email-0x7f454c46@gmail.com

Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

include/linux/ftrace.h

@@ -164,7 +164,6 @@ struct ftrace_ops {
 	ftrace_func_t			saved_func;
 	int __percpu			*disabled;
 #ifdef CONFIG_DYNAMIC_FTRACE
-	int				nr_trampolines;
 	struct ftrace_ops_hash		local_hash;
 	struct ftrace_ops_hash		*func_hash;
 	struct ftrace_ops_hash		old_hash;