[STM32L1] Make device.h a common file

Author: Laurent MEUNIER

hal/targets/hal/TARGET_STM/TARGET_STM32L1/TARGET_NUCLEO_L152RE/device.h

@@ -32,22 +32,9 @@
 #ifndef MBED_DEVICE_H
 #define MBED_DEVICE_H
 
-
-
-
-
-
-
-
-
-
 //=======================================
-
 #define DEVICE_ID_LENGTH       24
 
-
-
-
 #include "objects.h"
 
 #endif