Fix MISRA rule 8.4 Part 2

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=juno LOG_LEVEL=50 all

Change-Id: Ic8f611da734f356566e8208053296e6c62b54709
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
diff --git a/plat/arm/board/juno/juno_trng.c b/plat/arm/board/juno/juno_trng.c
index 124821b..d9ad1d4 100644
--- a/plat/arm/board/juno/juno_trng.c
+++ b/plat/arm/board/juno/juno_trng.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -8,6 +8,7 @@
 #include <mmio.h>
 #include <string.h>
 #include <utils_def.h>
+#include "juno_decl.h"
 #include "juno_def.h"
 
 #define NSAMPLE_CLOCKS	1 /* min 1 cycle, max 231 cycles */