extmod/utime_mphal: ticks_diff/ticks_add: Don't hardcode 32-bit types.

Use normal mp_int_t/mp_uint_t types, algorithms (hm, formulas) can work
with any type width.

extmod/utime_mphal.c

@@ -87,11 +87,11 @@ MP_DEFINE_CONST_FUN_OBJ_0(mp_utime_ticks_cpu_obj, time_ticks_cpu);
 
 STATIC mp_obj_t time_ticks_diff(mp_obj_t end_in, mp_obj_t start_in) {
     // we assume that the arguments come from ticks_xx so are small ints
-    uint32_t start = MP_OBJ_SMALL_INT_VALUE(start_in);
-    uint32_t end = MP_OBJ_SMALL_INT_VALUE(end_in);
+    mp_uint_t start = MP_OBJ_SMALL_INT_VALUE(start_in);
+    mp_uint_t end = MP_OBJ_SMALL_INT_VALUE(end_in);
     // Optimized formula avoiding if conditions. We adjust difference "forward",
     // wrap it around and adjust back.
-    int32_t diff = ((end - start + MICROPY_PY_UTIME_TICKS_PERIOD / 2) & (MICROPY_PY_UTIME_TICKS_PERIOD - 1))
+    mp_int_t diff = ((end - start + MICROPY_PY_UTIME_TICKS_PERIOD / 2) & (MICROPY_PY_UTIME_TICKS_PERIOD - 1))
                    - MICROPY_PY_UTIME_TICKS_PERIOD / 2;
     return MP_OBJ_NEW_SMALL_INT(diff);
 }
@@ -99,8 +99,8 @@ MP_DEFINE_CONST_FUN_OBJ_2(mp_utime_ticks_diff_obj, time_ticks_diff);
 
 STATIC mp_obj_t time_ticks_add(mp_obj_t ticks_in, mp_obj_t delta_in) {
     // we assume that first argument come from ticks_xx so is small int
-    uint32_t ticks = MP_OBJ_SMALL_INT_VALUE(ticks_in);
-    uint32_t delta = (uint32_t)mp_obj_get_int(delta_in);
+    mp_uint_t ticks = MP_OBJ_SMALL_INT_VALUE(ticks_in);
+    mp_uint_t delta = mp_obj_get_int(delta_in);
     return MP_OBJ_NEW_SMALL_INT((ticks + delta) & (MICROPY_PY_UTIME_TICKS_PERIOD - 1));
 }
 MP_DEFINE_CONST_FUN_OBJ_2(mp_utime_ticks_add_obj, time_ticks_add);