refactor: mbedtls: Remove redundant MBEDTLS_CONFIG_FILE

MBEDTLS_CONFIG_FILE is chosen when MBEDTLS_DIR is specified,
adding a redundant MBEDTLS_CONFIG_FILE name can cause
problem when we rename a config file or have more
than one config file.

Change-Id: I8bc6c27547e78a3506036b46bd9e12c8665a7147
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
(cherry picked from commit 8841f11a8ad466f9a1454c800a4a67b920e6f24e)
diff --git a/tf_config/fvp-tbb-mbedtls b/tf_config/fvp-tbb-mbedtls
index b9f65c9..8a40e81 100644
--- a/tf_config/fvp-tbb-mbedtls
+++ b/tf_config/fvp-tbb-mbedtls
@@ -1,7 +1,6 @@
 ARM_ROTPK_LOCATION=devel_rsa
 CROSS_COMPILE=aarch64-none-elf-
 GENERATE_COT=1
-MBEDTLS_CONFIG_FILE=\"${tf_root}/include/drivers/auth/mbedtls/mbedtls_config.h\"
 PLAT=fvp
 ROT_KEY=plat/arm/board/common/rotpk/arm_rotprivk_rsa.pem
 TRUSTED_BOARD_BOOT=1
diff --git a/tf_config/fvp-tbb-mbedtls-romlib b/tf_config/fvp-tbb-mbedtls-romlib
index 18f6e03..b7d8162 100644
--- a/tf_config/fvp-tbb-mbedtls-romlib
+++ b/tf_config/fvp-tbb-mbedtls-romlib
@@ -1,7 +1,6 @@
 ARM_ROTPK_LOCATION=devel_rsa
 CROSS_COMPILE=aarch64-none-elf-
 GENERATE_COT=1
-MBEDTLS_CONFIG_FILE=\"${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