wifi: mac80211: export ieee80211_purge_tx_queue() for drivers

wifi: mac80211: export ieee80211_purge_tx_queue() for drivers

commit 53bc1b73b67836ac9867f93dee7a443986b4a94f upstream.

Drivers need to purge TX SKB when stopping. Using skb_queue_purge() can't
report TX status to mac80211, causing ieee80211_free_ack_frame() warns
"Have pending ack frames!". Export ieee80211_purge_tx_queue() for drivers
to not have to reimplement it.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240822014255.10211-1-pkshih@realtek.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>