refactor(mbedtls): avoid including MBEDTLS_CONFIG_FILE

Currently we include MBEDTLS_CONFIG_FILE directly and if a custom
config file is used it will included.

However from mbedtls-3.x onwards it discourages usage of
MBEDTLS_CONFIG_FILE include directly, so to resolve this and keep 2.28
compatibility include version.h which would include the custom config
file if present and also would expose us with mbedtls-major-version
number which could be used for selecting features and functions for
mbedtls 2.28 or 3.3

Change-Id: I029992311be2a38b588ebbb350875b03ea29acdb
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/lib/fconf/fconf_cot_getter.c b/lib/fconf/fconf_cot_getter.c
index ae59d8c..1033018 100644
--- a/lib/fconf/fconf_cot_getter.c
+++ b/lib/fconf/fconf_cot_getter.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2022, Arm Limited. All rights reserved.
+ * Copyright (c) 2020-2023, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,8 +7,10 @@
 #include <assert.h>
 #include <stddef.h>
 
+#include <mbedtls/version.h>
+
 #include <common/fdt_wrappers.h>
-#include MBEDTLS_CONFIG_FILE
+#include <common/tbbr/cot_def.h>
 #include <drivers/auth/auth_mod.h>
 #include <lib/fconf/fconf.h>
 #include <lib/object_pool.h>