Note that the translation that tearma.ie gives for The Irish Wolfhound Club of Ireland is Cumann Cú Faoil na hÉireann, so it appears that cú faoil has two meanings — either a wolfhound in general, or an Irish wolfhound in particular — so PatHargan’s point is valid.
A quick search found "faoil" as either the genitive singular or the dative plural (discounting vocative and nominative since they wouldn't make sense)
gen. "a dog of a wolf" dat. "a dog for wolves"
Since wolfhounds were bred to hunt wolves (not bred from wolves) the construction is probably dative