The question is, whether it is an alternative spelling or simply a misspelling of a name, and is google the place to determine whether something is an alternative spelling. For instance, there are sites that refer to William Shakespear, even though the contemporary conventional form is Shakespeare.
As for Adolf/Adolf Hitler, there are two reason that it would be spelled with ph--1) the person spelling it is using the English, rather than the German, version of the name, though I can't really see a justification for this: we write Johann Wolfgang von Goethe, not John Wolfgang, and Konrad Adenauer, not Conrad (although admittedly, there are some instances where the English variant of a name is commonplace, i.e., William Tell); 2) the more likely, that the person either didn't know or made a mistake. I don't think we need to record misspellings, otherwise we can get stuck up with every variant typo, incl. Jospeh Goebbels.
Danny