net80211/drivers: improve ieee80211_rx_stats for band

[bz]

Summary

While IEEE80211_R_BAND was defined, there was no place to store the
band. Add a field for that, adjust ieee80211_lookup_channel_rxstatus()
to require it, and update drivers passing "R_{FREQ|IEEE}" in already to
provide the band as well. For the moment keep the fall-back code
requiring all three fields.

Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks

[bz]

This is just another gap-filling change I found buried in a dev-tree.
I've adjusted the remaining drivers (not all tested).

Historical remark:
In general I'd love to have seen "ieee80211_rx_stats" kept the same as seen in drivers rather than mostly remodeling it after what is there and changing names for no good and missing bits.
Just makes any porting effort harder having to map or sed-replace things.

[bz]

Anyone? Otherwise this will go in soon-ish.