build(fvp): specify MBEDTLS_CONFIG_FILE explicitly via build option

Change-Id: Ia74252f5eb895ae1cff5705d81c91dacd0827d83
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/tf_config/fvp-tbb-mbedtls b/tf_config/fvp-tbb-mbedtls
index 8a40e81..b9f65c9 100644
--- a/tf_config/fvp-tbb-mbedtls
+++ b/tf_config/fvp-tbb-mbedtls
@@ -1,6 +1,7 @@
 ARM_ROTPK_LOCATION=devel_rsa
 CROSS_COMPILE=aarch64-none-elf-
 GENERATE_COT=1
+MBEDTLS_CONFIG_FILE=\"${tf_root}/include/drivers/auth/mbedtls/mbedtls_config.h\"
 PLAT=fvp
 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem
 TRUSTED_BOARD_BOOT=1
diff --git a/tf_config/fvp-tbb-mbedtls-romlib b/tf_config/fvp-tbb-mbedtls-romlib
index b7d8162..18f6e03 100644
--- a/tf_config/fvp-tbb-mbedtls-romlib
+++ b/tf_config/fvp-tbb-mbedtls-romlib
@@ -1,6 +1,7 @@
 ARM_ROTPK_LOCATION=devel_rsa
 CROSS_COMPILE=aarch64-none-elf-
 GENERATE_COT=1
+MBEDTLS_CONFIG_FILE=\"${tf_root}/include/drivers/auth/mbedtls/mbedtls_config.h\"
 PLAT=fvp
 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem
 TRUSTED_BOARD_BOOT=1