Instead of comparing the lower and higher addresses of all the multicast entries to decide if the IFF_ALLMULTI flag should be set, check if there is at least one real range between them.
Instead of comparing the lower and higher addresses of all the multicast
entries to decide if the IFF_ALLMULTI flag should be set, check if there
is at least one real range between them.

Tested by naddy@

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars