boot: Update Nordic's license identifier tag

Nordic had changed its license identifier to new
more accurate id: LicenseRef-Nordic-5-Clause.
Old identifiers should be updated.

Signed-off-by: Dominik Kilian <Dominik.Kilian@nordicsemi.no>

ext/nrf/cc310_glue.c

@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2019 Nordic Semiconductor ASA
  *
- * SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 
 #include "cc310_glue.h"

ext/nrf/cc310_glue.h

@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2019 Nordic Semiconductor ASA
  *
- * SPDX-License-Identifier: LicenseRef-BSD-5-Clause-Nordic
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
 #ifndef NRF_CC310_GLUE_H__
 #define NRF_CC310_GLUE_H__