debugfs entries in cfg80211

Hi Johannes,

While reworking brcmfmac I stumbled on debugfs code in cfg80211, which 
creates the debugfs dir for the wiphy instance. It also creates a couple 
of entries, ie. rts and fragmentation threshold and retry limits. How 
useful are these as I suspect it is pretty old cruft and iw can obtain 
the information as well. Can it be removed.

Regards,
Arend