Merge pull request #2100 from jamike/fix_NUCLEO_F303K8_MBED_16

[NUCLEO_F303K8] fix MBED_16.

Author: 0xc0170

hal/targets/hal/TARGET_STM/TARGET_STM32F3/TARGET_NUCLEO_F303K8/device.h

@@ -31,13 +31,7 @@
  */
 #ifndef MBED_DEVICE_H
 #define MBED_DEVICE_H
-
-
-
-
-
-
-
+#define DEVICE_RTC_LSI 1