wifi: rtw89: flush TX queue before deleting key

wifi: rtw89: flush TX queue before deleting key

In the wpa_supplicant rekey flow, it sends an EAPOL packet 4/4 through
nl80211_tx_control_port() and triggers wake_tx_queue() in the driver.
Then, it sends nl80211_new_key() to configure a new key in mac80211.
However, in wake_tx_queue(), a workqueue is used to process the TX packet,
which might cause the driver to process the EAPOL packet later than
nl80211_new_key(). This results in the EAPOL packet 4/4 being transmitted
with the new key and IV, causing it to be dropped by the AP. Therefore,
needs to flush TX queue before deleting the old key to ensure that the
EAPOL 4/4 packet is transmitted using the old key.

Signed-off-by: Chih-Kang Chang <gary.chang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20251114060128.35363-2-pkshih@realtek.com