Remove declaration of inf_tid_to_proc

inf_tid_to_proc is not defined at all.  This patch is to remove its
declaration.
gdb:

2014-01-07  Yao Qi  <yao@codesourcery.com>

	* gnu-nat.c (inf_tid_to_proc): Remove declaration.

gdb/ChangeLog

@@ -1,3 +1,7 @@
+2014-01-07  Yao Qi  <yao@codesourcery.com>
+
+	* gnu-nat.c (inf_tid_to_proc): Remove declaration.
+
 2014-01-07  Yao Qi  <yao@codesourcery.com>
 
 	* gnu-nat.c (_initialize_gnu_nat): Declare.

gdb/gnu-nat.c

@@ -96,7 +96,6 @@ void inf_set_pid (struct inf *inf, pid_t pid);
 void inf_validate_procs (struct inf *inf);
 void inf_steal_exc_ports (struct inf *inf);
 void inf_restore_exc_ports (struct inf *inf);
-struct proc *inf_tid_to_proc (struct inf *inf, int tid);
 void inf_set_threads_resume_sc (struct inf *inf,
 				struct proc *run_thread,
 				int run_others);