Cellular: Added missing MDMRTS and MDMCTS for TARGET_MTB_ADV_WISE_1570.

Author: Teppo Järvelin

targets/TARGET_STM/TARGET_STM32L4/TARGET_STM32L486xG/TARGET_MTB_ADV_WISE_1570/PinNames.h

@@ -261,6 +261,8 @@ typedef enum {
     P_73            = WAKE,
     P_74            = NC,
     P_75            = NC,
+    MDMRTS          = NC,
+    MDMCTS          = NC,
 
 } PinName;