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: I32b223251b8bf5924149d89431a65d3405a73d3e
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>

plat/arm/common/arm_dyn_cfg_helpers.c

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <arm_dyn_cfg_helpers.h>
 #include <assert.h>
 #include <desc_image_load.h>
 #include <fdt_wrappers.h>