C++11 style initializer for SerialBase

Kudos to Kevin Bracey, as her his suggestion - we can drop the initializer
list if we just set the values directly in the SerialBase.h. No need to
worry about the "right order" after that.

(One tab to space issue with _tx_pin(tx) fixed).

Author: Janne Kiiskila

drivers/SerialBase.h

@@ -329,25 +329,28 @@ class SerialBase : private NonCopyable<SerialBase> {
 
 #if DEVICE_SERIAL_ASYNCH
     CThunk<SerialBase> _thunk_irq;
-    DMAUsage _tx_usage;
-    DMAUsage _rx_usage;
+    DMAUsage _tx_usage = DMA_USAGE_NEVER;
+    DMAUsage _rx_usage = DMA_USAGE_NEVER;
     event_callback_t _tx_callback;
     event_callback_t _rx_callback;
-    bool _tx_asynch_set;
-    bool _rx_asynch_set;
+    bool _tx_asynch_set = false;
+    bool _rx_asynch_set = false;
 #endif
-#if DEVICE_SERIAL_FC
-    Flow             _flow_type;
-    PinName          _flow1;
-    PinName          _flow2;
-#endif
-    serial_t         _serial;
+
+    serial_t         _serial {};
     Callback<void()> _irq[IrqCnt];
     int              _baud;
-    bool             _rx_enabled;
-    bool             _tx_enabled;
+    bool             _rx_enabled = true;
+    bool             _tx_enabled = true;
     const PinName    _tx_pin;
     const PinName    _rx_pin;
+
+#if DEVICE_SERIAL_FC
+    Flow             _flow_type = Disabled;
+    PinName          _flow1 = NC;
+    PinName          _flow2 = NC;
+#endif
+
 #endif
 };
 

drivers/source/SerialBase.cpp

@@ -25,20 +25,9 @@ namespace mbed {
 
 SerialBase::SerialBase(PinName tx, PinName rx, int baud) :
 #if DEVICE_SERIAL_ASYNCH
-    _thunk_irq(this), _tx_usage(DMA_USAGE_NEVER),
-    _rx_usage(DMA_USAGE_NEVER), _tx_callback(NULL),
-    _rx_callback(NULL), _tx_asynch_set(false),
-    _rx_asynch_set(false),
+    _thunk_irq(this),
 #endif
-#if DEVICE_SERIAL_FC
-    _flow_type(Disabled),
-    _flow1(NC),
-    _flow2(NC),
-#endif
-    _serial(),
     _baud(baud),
-    _rx_enabled(true),
-    _tx_enabled(true),
     _tx_pin(tx),
     _rx_pin(rx)
 {