Initialize pAdvertising after NimBLEDevice::init() (#545)

Initializing the pAdvertising variable from NimBLEDevice::init while defining it as a globally results in the name getting truncated.

Author: ankgt

examples/NimBLE_Service_Data_Advertiser/NimBLE_Service_Data_Advertiser.ino

@@ -12,14 +12,15 @@
 #define SERVICE_UUID "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
 
 static NimBLEUUID dataUuid(SERVICE_UUID);
-static NimBLEAdvertising *pAdvertising = NimBLEDevice::getAdvertising();
+static NimBLEAdvertising *pAdvertising = nullptr;
 static uint32_t count = 0;
 
 void setup() {
   Serial.begin(115200);
   Serial.println("Starting BLE work!");
 
   NimBLEDevice::init("svc data");
+  pAdvertising = NimBLEDevice::getAdvertising();
 }
 
 void loop() {