esp8266: Fix reading of pin object for GPIO16.

Pin(16) now works as an input.
diff --git a/esp8266/modpybpin.c b/esp8266/modpybpin.c
index 166d6f5..7940686 100644
--- a/esp8266/modpybpin.c
+++ b/esp8266/modpybpin.c
@@ -301,7 +301,7 @@
     pyb_pin_obj_t *self = self_in;
     if (n_args == 0) {
         // get pin
-        return MP_OBJ_NEW_SMALL_INT(GPIO_INPUT_GET(self->phys_port));
+        return MP_OBJ_NEW_SMALL_INT(pin_get(self->phys_port));
     } else {
         // set pin
         pin_set(self->phys_port, mp_obj_is_true(args[0]));