plat/arm: juno: Implement methods to retrieve soc-id information

Implemented platform functions to retrieve the soc-id information
for juno platform

Change-Id: Ie677120710b45e202a2d63a954459ece8a64b353
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/plat/arm/board/juno/juno_def.h b/plat/arm/board/juno/juno_def.h
index 3b34a9f..ddf99dc 100644
--- a/plat/arm/board/juno/juno_def.h
+++ b/plat/arm/board/juno/juno_def.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2019, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -9,6 +9,11 @@
 
 #include <lib/utils_def.h>
 
+/******************************************************************************
+ * Definition of platform soc id
+ *****************************************************************************/
+#define JUNO_SOC_ID     1
+
 /*******************************************************************************
  * Juno memory map related constants
  ******************************************************************************/