plat: xilinx: versal: Move versal_private.h to include directory

Move versal_private.h to platform specific include directory.
Also, rename it to plat_private.h instead of having platform
name. So, it can be used to common source files which needs
platform specific data.

Signed-off-by: Tejas Patel <tejas.patel@xilinx.com>
Signed-off-by: Jolly Shah <jolly.shah@xilinx.com>
Change-Id: I65eefbea7722ffa2760b992491c00eebef5bcef4
diff --git a/plat/xilinx/versal/versal_gicv3.c b/plat/xilinx/versal/versal_gicv3.c
index dcf23b4..08e7cf9 100644
--- a/plat/xilinx/versal/versal_gicv3.c
+++ b/plat/xilinx/versal/versal_gicv3.c
@@ -1,9 +1,10 @@
 /*
- * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2018-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <plat_private.h>
 #include <platform_def.h>
 
 #include <common/interrupt_props.h>
@@ -11,8 +12,6 @@
 #include <lib/utils.h>
 #include <plat/common/platform.h>
 
-#include "versal_private.h"
-
 /******************************************************************************
  * The following functions are defined as weak to allow a platform to override
  * the way the GICv3 driver is initialised and used.