https://bugzilla.redhat.com/show_bug.cgi?id=1214369
https://bugzilla.redhat.com/show_bug.cgi?id=1458638

Historically, we've always supported memAccess for domains backed
by hugepages. However, somewhere along the way we've regressed
and stopped allowing such configuration. Fix it.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>