Remove MBEDTLS_DES_ALT

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 193262b..83b9c92 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -351,7 +351,6 @@
 //#define MBEDTLS_TIMING_ALT
 
 //#define MBEDTLS_CMAC_ALT
-//#define MBEDTLS_DES_ALT
 //#define MBEDTLS_NIST_KW_ALT
 //#define MBEDTLS_MD5_ALT
 //#define MBEDTLS_RIPEMD160_ALT
diff --git a/tests/include/alt-dummy/des_alt.h b/tests/include/alt-dummy/des_alt.h
deleted file mode 100644
index d079861..0000000
--- a/tests/include/alt-dummy/des_alt.h
+++ /dev/null
@@ -1,22 +0,0 @@
-/* des_alt.h with dummy types for MBEDTLS_DES_ALT */
-/*
- *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
- *
- */
-
-#ifndef DES_ALT_H
-#define DES_ALT_H
-
-typedef struct mbedtls_des_context {
-    int dummy;
-}
-mbedtls_des_context;
-
-typedef struct mbedtls_des3_context {
-    int dummy;
-}
-mbedtls_des3_context;
-
-
-#endif /* des_alt.h */
diff --git a/tf-psa-crypto/drivers/builtin/include/mbedtls/des.h b/tf-psa-crypto/drivers/builtin/include/mbedtls/des.h
index 2b097a1..c2d910c 100644
--- a/tf-psa-crypto/drivers/builtin/include/mbedtls/des.h
+++ b/tf-psa-crypto/drivers/builtin/include/mbedtls/des.h
@@ -34,10 +34,6 @@
 extern "C" {
 #endif
 
-#if !defined(MBEDTLS_DES_ALT)
-// Regular implementation
-//
-
 /**
  * \brief          DES context structure
  *
@@ -62,9 +58,6 @@
 }
 mbedtls_des3_context;
 
-#else  /* MBEDTLS_DES_ALT */
-#include "des_alt.h"
-#endif /* MBEDTLS_DES_ALT */
 
 /**
  * \brief          Initialize DES context
diff --git a/tf-psa-crypto/drivers/builtin/src/des.c b/tf-psa-crypto/drivers/builtin/src/des.c
index f0032b3..5410bd3 100644
--- a/tf-psa-crypto/drivers/builtin/src/des.c
+++ b/tf-psa-crypto/drivers/builtin/src/des.c
@@ -23,8 +23,6 @@
 
 #include "mbedtls/platform.h"
 
-#if !defined(MBEDTLS_DES_ALT)
-
 /*
  * Expanded DES S-boxes
  */
@@ -773,8 +771,6 @@
 }
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
-#endif /* !MBEDTLS_DES_ALT */
-
 #if defined(MBEDTLS_SELF_TEST)
 /*
  * DES and 3DES test vectors from: