Clarify comments on subjectAltName types

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/library/x509.c b/library/x509.c
index 9f0dc62..b859df9 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -1227,8 +1227,9 @@
  *      nameAssigner            [0]     DirectoryString OPTIONAL,
  *      partyName               [1]     DirectoryString }
  *
- * NOTE: we list all types, but only use "dnsName", "otherName" and
- * "uniformResourceIdentifier", as defined in RFC 5280, at this point.
+ * We list all types, but use the following GeneralName types from RFC 5280:
+ * "dnsName", "uniformResourceIdentifier" and "hardware_module_name"
+ * of type "otherName", as defined in RFC 4108.
  */
 int mbedtls_x509_get_subject_alt_name(unsigned char **p,
                                       const unsigned char *end,