tracing/trace_stack: fix the number of entries in the header

The last entry in the stack_dump_trace is ULONG_MAX, which is not
a valid entry, but max_stack_trace.nr_entries has accounted for it.
So when printing the header, we should decrease it by one.
Before fix, print as following, for example:

	Depth    Size   Location    (53 entries)	<--- should be 52
	-----    ----   --------
  0)     3264     108   update_wall_time+0x4d5/0x9a0
  ...
 51)       80      80   syscall_call+0x7/0xb
 ^^^
   it's correct.
Signed-off-by: walimis <walimisdev@gmail.com>
LKML-Reference: <1244016090-7814-1-git-send-email-walimisdev@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_stack.c

@@ -265,7 +265,7 @@ static int t_show(struct seq_file *m, void *v)
 		seq_printf(m, "        Depth    Size   Location"
 			   "    (%d entries)\n"
 			   "        -----    ----   --------\n",
-			   max_stack_trace.nr_entries);
+			   max_stack_trace.nr_entries - 1);
 
 		if (!stack_tracer_enabled && !max_stack_size)
 			print_disabled(m);