Change referenc funtion to include/mbedtls/ssl.h in note

Signed-off-by: Ben Taylor <ben.taylor@linaro.org>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 9cba94e..623ffd1 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -3366,7 +3366,7 @@
  *
  * \note           The restrictions are enforced for all certificates in the
  *                 chain. However, signatures in the handshake are not covered
- *                 by this setting but by \b mbedtls_ssl_conf_sig_hashes().
+ *                 by this setting but by \b mbedtls_ssl_conf_sig_algs().
  *
  * \param conf     SSL configuration
  * \param profile  Profile to use