wifi: mac80211: use safe list iteration in radar detect work

wifi: mac80211: use safe list iteration in radar detect work

The call to ieee80211_dfs_cac_cancel can cause the iterated chanctx to
be freed and removed from the list. Guard against this to avoid a
slab-use-after-free error.

Cc: stable@vger.kernel.org
Fixes: bca8bc0399ac ("wifi: mac80211: handle ieee80211_radar_detected() for MLO")
Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20260505151539.236d63a1b736.I35dbb9e96a2d4a480be208770fdd99ba3b817b79@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>