tracing: Remove unnecessary variable in print_graph_return

The "cpu" variable is declared at the start of the function and
also within a branch, with the exact same initialization.

Remove the local variable of the same name in the branch.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
LKML-Reference: <1266997226-6833-3-git-send-email-wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_functions_graph.c

@@ -855,7 +855,6 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 	int i;
 
 	if (data) {
-		int cpu = iter->cpu;
 		int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth);
 
 		/*