Nordic BLE: Add default parameter to get the local instance of nrF5xn

Author: pan-

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NRF51/source/nRF5xn.h

@@ -134,7 +134,7 @@ class nRF5xn : public BLEInstanceBase
     virtual void processEvents();
 
 public:
-    static nRF5xn& Instance(BLE::InstanceID_t instanceId);
+    static nRF5xn& Instance(BLE::InstanceID_t instanceId = BLE::DEFAULT_INSTANCE);
 
 private:
     bool              initialized;

features/FEATURE_BLE/targets/TARGET_NORDIC/TARGET_NRF52/source/nRF5xn.h

@@ -133,7 +133,7 @@ class nRF5xn : public BLEInstanceBase
     virtual void processEvents();
 
 public:
-    static nRF5xn& Instance(BLE::InstanceID_t instanceId);
+    static nRF5xn& Instance(BLE::InstanceID_t instanceId = BLE::DEFAULT_INSTANCE);
 
 private:
     bool              initialized;