Crypto build cleanup: remove INTERNAL_DES

In addition, rename des.c to des-internal.c to match in style with
SHA-1 conditionally built internal implementation.

src/crypto/des-internal.c

@@ -19,9 +19,6 @@
 #include "common.h"
 #include "crypto.h"
 
-
-#ifdef INTERNAL_DES
-
 /*
  * This implementation is based on a DES implementation included in
  * LibTomCrypt. The version here is modified to fit in wpa_supplicant/hostapd
@@ -475,5 +472,3 @@ void des3_decrypt(const u8 *crypt, const struct des3_key_s *key, u8 *plain)
 	WPA_PUT_BE32(plain, work[0]);
 	WPA_PUT_BE32(plain + 4, work[1]);
 }
-
-#endif /* INTERNAL_DES */

src/utils/build_config.h

@@ -55,7 +55,6 @@
 #define INTERNAL_SHA256
 #define INTERNAL_MD5
 #define INTERNAL_MD4
-#define INTERNAL_DES
 #define CONFIG_INTERNAL_X509
 #define CONFIG_CRYPTO_INTERNAL
 #endif /* USE_INTERNAL_CRYPTO */
@@ -71,7 +70,6 @@
 #define INTERNAL_AES
 #define INTERNAL_MD5
 #define INTERNAL_MD4
-#define INTERNAL_DES
 #define CONFIG_INTERNAL_LIBTOMMATH
 #define CONFIG_INTERNAL_X509
 #define EAP_TLS_FUNCS