Fix some X509 macro names
For some reason, during the great renaming, some names that should have been
prefixed with MBEDTLS_X509_ have only been prefixed with MBEDTLS_
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index 938910c..bb6d376 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -279,7 +279,7 @@
* \brief Check usage of certificate against keyUsage extension.
*
* \param crt Leaf certificate used.
- * \param usage Intended usage(s) (eg MBEDTLS_KU_KEY_ENCIPHERMENT before using the
+ * \param usage Intended usage(s) (eg MBEDTLS_X509_KU_KEY_ENCIPHERMENT before using the
* certificate to perform an RSA key exchange).
*
* \return 0 is these uses of the certificate are allowed,