stm32: Add casts when printing small integers.

All these arguments are of type `mp_{u,}int_t`, but the actual value is
always a small integer.  Cast it so that it can format with the `%d/%u`
formatter.

Before, the compiler plugin produced an error in the PYBD_SF6 build, which
is a nanboxing build with 64-bit ints.

Signed-off-by: Jeff Epler <jepler@gmail.com>

Author: jepler

ports/stm32/extint.c

@@ -760,7 +760,7 @@ static mp_obj_t extint_make_new(const mp_obj_type_t *type, size_t n_args, size_t
 
 static void extint_obj_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     extint_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_printf(print, "<ExtInt line=%u>", self->line);
+    mp_printf(print, "<ExtInt line=%u>", (int)self->line);
 }
 
 static const mp_rom_map_elem_t extint_locals_dict_table[] = {

ports/stm32/led.c

@@ -305,7 +305,7 @@ void led_debug(int n, int delay) {
 
 void led_obj_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     pyb_led_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_printf(print, "LED(%u)", self->led_id);
+    mp_printf(print, "LED(%u)", (int)self->led_id);
 }
 
 /// \classmethod \constructor(id)

ports/stm32/machine_uart.c

@@ -93,7 +93,7 @@ static void mp_machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_
         #endif
         {
             mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=",
-                self->uart_id, uart_get_baudrate(self), bits);
+                self->uart_id, uart_get_baudrate(self), (int)bits);
         }
         if (!(cr1 & USART_CR1_PCE)) {
             mp_print_str(print, "None");

ports/stm32/pin.c

@@ -232,7 +232,7 @@ static void pin_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t
             mp_uint_t af_idx = pin_get_af(self);
             const pin_af_obj_t *af_obj = pin_find_af_by_index(self, af_idx);
             if (af_obj == NULL) {
-                mp_printf(print, ", alt=%d)", af_idx);
+                mp_printf(print, ", alt=%d)", (int)af_idx);
             } else {
                 mp_printf(print, ", alt=Pin.%q)", af_obj->name);
             }

ports/stm32/timer.c

@@ -499,7 +499,7 @@ static uint32_t compute_dtg_from_ticks(mp_int_t ticks) {
 
 // Given the 8-bit value stored in the DTG field of the BDTR register, compute
 // the number of ticks.
-static mp_int_t compute_ticks_from_dtg(uint32_t dtg) {
+static unsigned compute_ticks_from_dtg(uint32_t dtg) {
     if ((dtg & 0x80) == 0) {
         return dtg & 0x7F;
     }