Remove struct print_one_inferior_data

struct print_one_inferior_data is not used, so remove it.
diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
index 9d084c3..446a4f4 100644
--- a/gdb/mi/mi-main.c
+++ b/gdb/mi/mi-main.c
@@ -622,12 +622,6 @@ collect_cores (struct thread_info *ti, void *xdata)
   return 0;
 }
 
-struct print_one_inferior_data
-{
-  int recurse;
-  const std::set<int> *inferiors;
-};
-
 static void
 print_one_inferior (struct inferior *inferior, bool recurse,
 		    const std::set<int> &ids)