Fix MISRA rule 8.4 Part 1

Rule 8.4: A compatible declaration shall be visible when
          an object or function with external linkage is defined

Fixed for:
	make DEBUG=1 PLAT=fvp LOG_LEVEL=50 all

Change-Id: I7c2ad3f5c015411c202605851240d5347e4cc8c7
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/plat/arm/common/arm_tzc400.c b/plat/arm/common/arm_tzc400.c
index cf13326..6b706be 100644
--- a/plat/arm/common/arm_tzc400.c
+++ b/plat/arm/common/arm_tzc400.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,6 +7,7 @@
 #include <arm_def.h>
 #include <arm_spm_def.h>
 #include <debug.h>
+#include <plat_arm.h>
 #include <platform_def.h>
 #include <tzc400.h>