wifi: cfg80211: remove chandef check in cfg80211_cac_event()

The current check only worked for AP mode, but we can do
radar detection in mesh as well (for example). We could
try to check this using wdev_chandef(), but we also don't
really care since the chandef is passed in and we have no
need to use it anymore (since we added the argument in
commit d2859df5 ("cfg80211/mac80211: DFS setup chandef
for cac event")).

Change-Id: I856e4344d5e64ff4d2eead0b4c53b11f264be9b8
Fixes: 7b0a0e3c ("wifi: cfg80211: do some rework towards MLO link APIs")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>