Fixed build by removing unnecessary include.

Author: Teppo Järvelin

features/cellular/easy_cellular/EasyCellularConnection.h

@@ -16,7 +16,6 @@
  */
 
 #ifndef EASY_CELLULAR_CONNECTION_H
-
 #define EASY_CELLULAR_CONNECTION_H
 
 #include "CellularConnectionFSM.h"

features/cellular/framework/AT/AT_CellularPower.cpp

@@ -20,7 +20,6 @@
 #include "CellularLog.h"
 #include "CellularTargets.h"
 #include "nsapi_types.h"
-#include CELLULAR_STRINGIFY(CELLULAR_DEVICE.h)
 
 static const int PSMTimerBits = 5;