Coverity: remove unnecessary header file includes

This patch removes unnecessary header file includes
discovered by Coverity HFA option.

Change-Id: I2827c37c1c24866c87db0e206e681900545925d4
Signed-off-by: Zelalem <zelalem.aweke@arm.com>
diff --git a/plat/arm/common/arm_nor_psci_mem_protect.c b/plat/arm/common/arm_nor_psci_mem_protect.c
index b9181eb..1fa234d 100644
--- a/plat/arm/common/arm_nor_psci_mem_protect.c
+++ b/plat/arm/common/arm_nor_psci_mem_protect.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,7 +9,6 @@
 #include <common/debug.h>
 #include <drivers/cfi/v2m_flash.h>
 #include <lib/psci/psci.h>
-#include <lib/mmio.h>
 #include <lib/utils.h>
 #include <plat/arm/common/plat_arm.h>