cpp_dummy_build: Remove X.509 dependency
#include "mbedtls/threading.h"
#include "mbedtls/timing.h"
#include "mbedtls/version.h"
-#include "mbedtls/x509.h"
-#include "mbedtls/x509_crl.h"
-#include "mbedtls/x509_crt.h"
-#include "mbedtls/x509_csr.h"
#include "mbedtls/xtea.h"
#if defined(MBEDTLS_PLATFORM_C)
