STM32F3: Correct UART4 and UART5 defines when using DEVICE_SERIAL_ASYNCH

Author: bscott-zebra

targets/TARGET_STM/TARGET_STM32F3/serial_api.c

@@ -578,14 +578,14 @@ static IRQn_Type serial_get_irq_n(serial_t *obj)
             irq_n = USART3_IRQn;
             break;
 #endif
-#if defined(USART4_BASE)
+#if defined(UART4_BASE)
         case 3:
-            irq_n = USART4_IRQn;
+            irq_n = UART4_IRQn;
             break;
 #endif
-#if defined(USART5_BASE)
+#if defined(UART5_BASE)
         case 4:
-            irq_n = USART5_IRQn;
+            irq_n = UART5_IRQn;
             break;
 #endif
         default: