wifi: nl80211: make nl80211_send_chandef non-static

Expose nl80211_send_chandef functionality for mac80211_hwsim or vendor
netlink can use it where needed.

Signed-off-by: Jaewan Kim <jaewan@google.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Link: https://lore.kernel.org/r/20230322131637.2633968-3-jaewan@google.com


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