add tls1_3 read certificate

Signed-off-by: Xiaofei Bai <xiaofei.bai@arm.com>
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 66fb26c..dbef6aa 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1627,6 +1627,12 @@
                                            unsigned hs_type,
                                            unsigned char **buf,
                                            size_t *buflen );
+
+/*
+ * Handler of TLS 1.3 server certificate message
+ */
+int mbedtls_ssl_tls13_process_certificate( mbedtls_ssl_context *ssl );
+
 /*
  * Write TLS 1.3 handshake message tail
  */