When clearing gamepad buffer, use the last button state, not 0

When reading the accumulated button presses in gamepad and gamepadshift,
don't clear the buffer to "no buttons pressed", but instead set it to
the current (last checked) state. This clears the accumulated presses,
but retains any ongoing ones.

This fixes #1935

Author: deshipu

shared-bindings/gamepad/GamePad.c

@@ -127,7 +127,7 @@ STATIC mp_obj_t gamepad_make_new(const mp_obj_type_t *type, size_t n_args,
 STATIC mp_obj_t gamepad_get_pressed(mp_obj_t self_in) {
     gamepad_obj_t* gamepad_singleton = MP_STATE_VM(gamepad_singleton);
     mp_obj_t pressed = MP_OBJ_NEW_SMALL_INT(gamepad_singleton->pressed);
-    gamepad_singleton->pressed = 0;
+    gamepad_singleton->pressed = gamepad_singleton->last;
     return pressed;
 }
 MP_DEFINE_CONST_FUN_OBJ_1(gamepad_get_pressed_obj, gamepad_get_pressed);

shared-bindings/gamepadshift/GamePadShift.c

@@ -94,7 +94,7 @@ STATIC mp_obj_t gamepadshift_make_new(const mp_obj_type_t *type, size_t n_args,
 STATIC mp_obj_t gamepadshift_get_pressed(mp_obj_t self_in) {
     gamepadshift_obj_t* gamepad_singleton = MP_STATE_VM(gamepad_singleton);
     mp_obj_t pressed = MP_OBJ_NEW_SMALL_INT(gamepad_singleton->pressed);
-    gamepad_singleton->pressed = 0;
+    gamepad_singleton->pressed = gamepad_singleton->last;
     return pressed;
 }
 MP_DEFINE_CONST_FUN_OBJ_1(gamepadshift_get_pressed_obj, gamepadshift_get_pressed);