I thought those were Goths. But seriously, the languages were right smack up against each other for a long time and the Celts came within a gnat's butt of successfully invading the Italian peninsula.

That said:

A) The Celtic language spoken by Asterix's people and Old Irish were probably mutually incomprehensible and we have no reason to believe that any word with a similar meaning and a similar sound to the Irish bodhairim would have existed in the continental Celtic language.

and

2) The influence on the language would have been on Latin anyway, so we're still back to paturnia coming from something in Latin.