OpenSSL: Update session_secret callback to match OpenSSL 1.1.0 API

The SSL_CIPHER **cipher argument was marked const in OpenSSL 1.1.0
pre-release 2 similarly to how this is in BoringSSL. Fix build with that
in preparation for supporting OpenSSL 1.1.0.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

src/crypto/tls_openssl.c

@@ -4049,7 +4049,7 @@ int tls_global_set_params(void *tls_ctx,
  * commented out unless explicitly needed for EAP-FAST in order to be able to
  * build this file with unmodified openssl. */
 
-#ifdef OPENSSL_IS_BORINGSSL
+#if defined(OPENSSL_IS_BORINGSSL) || OPENSSL_VERSION_NUMBER >= 0x10100000L
 static int tls_sess_sec_cb(SSL *s, void *secret, int *secret_len,
 			   STACK_OF(SSL_CIPHER) *peer_ciphers,
 			   const SSL_CIPHER **cipher, void *arg)