Platform: Update the include statements

Change the absolute including into relative path including
for platform sources.

Change-Id: I594577eae7689ea8ac6cb557d5b0b5a048ee9b4d
Signed-off-by: Mingyang Sun <mingyang.sun@arm.com>
diff --git a/platform/ext/common/template/tfm_rotpk.c b/platform/ext/common/template/tfm_rotpk.c
index 2f26281..72811a5 100644
--- a/platform/ext/common/template/tfm_rotpk.c
+++ b/platform/ext/common/template/tfm_rotpk.c
@@ -1,12 +1,12 @@
 /*
- * Copyright (c) 2019, Arm Limited. All rights reserved.
+ * Copyright (c) 2019-2020, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  *
  */
 
 #include <stdint.h>
-#include "platform/include/tfm_plat_crypto_keys.h"
+#include "tfm_plat_crypto_keys.h"
 /**
  * \file tfm_rotpk.c
  *