This is incorrect. Herodotus refers to the population of Southern Portugal as "Kynetes", and he mentions them as distinct from the Keltoi. The problem is that Herodotus was geographically challenged. He claims that the Danube (Istros) originates in the lands of the Keltoi (a statement which by
itself is correct), but he somehow seems to assume that it flew across all the length of Europe.
http://upload.wikimedia.org/wikipedia/de/7/74/Orbisherodoti-sb.jpg
However, one has to add that Herodotus lived in the 5th century BC and by that time, the knowledge of the Greeks of the real extend of Western Europe was probably limited.
Well, let me say that I agree that Tartessian wasn't related with Phoenician, but I don't think it was Celtic, either. There are considerable concentrations of E1b, G, J1, J2 and T in the Southwest, and from that perspective I find it very compelling they were a non-Indo-European people.