wifi: cfg80211: restrict operation during radar detection

Just like it's not currently possible to start radar
detection while already operating, it shouldn't be
possible to start operating while radar detection is
running. Fix that.

Also, improve the check whether operating (carrier
might not be up if e.g. attempting to join IBSS).

Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240506211158.ae8dca3d0d6c.I7c70a66a5fbdbc63a78fee8a34f31d1995491bc3@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>