Add MBEDTLS_ALLOW_PRIVATE_ACCESS to test programs

Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index e160feb..a3e306c 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -17,6 +17,8 @@
  *  limitations under the License.
  */
 
+#define MBEDTLS_ALLOW_PRIVATE_ACCESS
+
 #if !defined(MBEDTLS_CONFIG_FILE)
 #include "mbedtls/config.h"
 #else