__assign_str handling

In 6.10, the tracing __assign_str() macro lots its second argument.

We simply made a patch (for cfg80211, mac80211 and iwlwifi) to put it
back under ifdef, but maybe someone else has any other ideas?

The big problem is that it's defined/undefined/redefined, so can't even
override it (if it were even possible, since we don't generally know
what the argument should be).

johannes