function_graph: Remove unnecessary initialization in ftrace_graph_ret_addr()

After the commit 29c1c24 ("function_graph: Fix up ftrace_graph_ret_addr()")
ftrace_graph_ret_addr() doesn't need to initialize "int i" at the start.

Cc: Masami Hiramatsu <[email protected]>
Cc: Puranjay Mohan <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

Author: oleg-nesterov

kernel/trace/fgraph.c

@@ -930,7 +930,7 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx,
 {
 	struct ftrace_ret_stack *ret_stack;
 	unsigned long return_handler = (unsigned long)dereference_kernel_function_descriptor(return_to_handler);
-	int i = task->curr_ret_stack;
+	int i;
 
 	if (ret != return_handler)
 		return ret;