stmhal/pin_named_pins: Remove unreachable print function.

There are never any instances of these objects so there is no need to have
a print function.

stmhal/pin_named_pins.c

@@ -31,22 +31,15 @@
 #include "py/mphal.h"
 #include "pin.h"
 
-STATIC void pin_named_pins_obj_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
-    pin_named_pins_obj_t *self = self_in;
-    mp_printf(print, "<Pin.%q>", self->name);
-}
-
 const mp_obj_type_t pin_cpu_pins_obj_type = {
     { &mp_type_type },
     .name = MP_QSTR_cpu,
-    .print = pin_named_pins_obj_print,
     .locals_dict = (mp_obj_t)&pin_cpu_pins_locals_dict,
 };
 
 const mp_obj_type_t pin_board_pins_obj_type = {
     { &mp_type_type },
     .name = MP_QSTR_board,
-    .print = pin_named_pins_obj_print,
     .locals_dict = (mp_obj_t)&pin_board_pins_locals_dict,
 };