RFC5280 does not state that the `revocationDate` should be checked.
In addition, when no time source is available (i.e., when MBEDTLS_HAVE_TIME_DATE is not defined), `mbedtls_x509_time_is_past` always returns 0. This results in the CRL not being checked at all.
https://tools.ietf.org/html/rfc5280
Signed-off-by: Raoul Strackx <raoul.strackx@fortanix.com>
