tls13: add ecdh_read_public

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ecdh_misc.h b/library/ecdh_misc.h
index d1342f8..94d3139 100644
--- a/library/ecdh_misc.h
+++ b/library/ecdh_misc.h
@@ -43,6 +43,12 @@
                                     int ( *f_rng )( void *, unsigned char *, size_t ),
                                     void *p_rng );
 
+/*
+ * TLS 1.3 version of mbedtls_ecdh_read_public in ecdh.h
+ */
+int mbedtls_ecdh_tls1_3_read_public( mbedtls_ecdh_context *ctx,
+                                     const unsigned char *buf,
+                                     size_t blen );
 
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */