ARM Platforms: Load HW_CONFIG in BL2

The patch adds the necessary changes to load HW_CONFIG in BL2 for
ARM Platforms :

1. The load address of HW_CONFIG is specified via the `hw_config_addr`
property in TB_FW_CONFIG is loaded by BL1. The `hw_config_max_size`
property defines the maximum size to be expected for the HW_CONFIG.
The `arm_dyn_cfg_helpers.c` and corresponding header implements
utility functions to parse these DT properties defined.
The `arm_dyn_cfg.c` implements wrappers to these helpers to enable
them to be invoked from ARM platform layer.

2. `HW_CONFIG` is added to the `bl2_mem_params_descs[]` array which is
the list of images to be loaded by BL2.

3. The `libfdt` sources are now included when BL2 is built

4. A new helper `populate_next_bl_params_config()` is introduced in
desc_image_load.c to populate the subsequent executable BL images
with the `hw_config` and the corresponding `fw_config` if available.
The `plat_get_next_bl_params()` API for ARM platforms is modified to
invoke this new helper.

5. The implementation of `bl2_early_platform_setup2()` is modified to
consider `arg0` as well in addition to `arg1` passed from BL1.

6. Bump up the BL2 size for Juno to accommodate the inclusion of libfdt.

Change-Id: I80f1554adec41753e0d179a5237364f04fe13a3f
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/plat/arm/common/arm_image_load.c b/plat/arm/common/arm_image_load.c
index 03e4b4f..916fa8d 100644
--- a/plat/arm/common/arm_image_load.c
+++ b/plat/arm/common/arm_image_load.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,6 +7,7 @@
 #include <arm_def.h>
 #include <bl_common.h>
 #include <desc_image_load.h>
+#include <plat_arm.h>
 #include <platform.h>
 
 
@@ -37,5 +38,8 @@
  ******************************************************************************/
 bl_params_t *plat_get_next_bl_params(void)
 {
-	return get_next_bl_params_from_mem_params_desc();
+	bl_params_t *next_bl_params = get_next_bl_params_from_mem_params_desc();
+
+	populate_next_bl_params_config(next_bl_params);
+	return next_bl_params;
 }