tests: benchmarks: mbedtls: Support legacy API

The contents of mbedtls_ecdh_context have changed in newer versions of
the library.  For now, we can work with the old version by adding a
configuration define.  It is unclear how long this will continue to
work.

Signed-off-by: David Brown <[email protected]>

Author: d3zd3z

tests/benchmarks/mbedtls/src/benchmark.c

@@ -19,6 +19,7 @@
  *  This file is part of mbed TLS (https://tls.mbed.org)
  */
 
+#define MBEDTLS_ECDH_LEGACY_CONTEXT
 #if !defined(CONFIG_MBEDTLS_CFG_FILE)
 #include "mbedtls/config.h"
 #else