wifi: rtw89: Add missing check for alloc_workqueue

Add check for the return value of alloc_workqueue since it may return
NULL pointer.
Moreover, add destroy_workqueue when rtw89_load_firmware fails.

Fixes: e3ec7017 ("rtw89: add Realtek 802.11ax driver")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230104142901.1611-1-jiasheng@iscas.ac.cn

drivers/net/wireless/realtek/rtw89/core.c

@@ -3135,6 +3135,8 @@ int rtw89_core_init(struct rtw89_dev *rtwdev)
 	INIT_DELAYED_WORK(&rtwdev->cfo_track_work, rtw89_phy_cfo_track_work);
 	INIT_DELAYED_WORK(&rtwdev->forbid_ba_work, rtw89_forbid_ba_work);
 	rtwdev->txq_wq = alloc_workqueue("rtw89_tx_wq", WQ_UNBOUND | WQ_HIGHPRI, 0);
+	if (!rtwdev->txq_wq)
+		return -ENOMEM;
 	spin_lock_init(&rtwdev->ba_lock);
 	spin_lock_init(&rtwdev->rpwm_lock);
 	mutex_init(&rtwdev->mutex);
@@ -3160,6 +3162,7 @@ int rtw89_core_init(struct rtw89_dev *rtwdev)
 	ret = rtw89_load_firmware(rtwdev);
 	if (ret) {
 		rtw89_warn(rtwdev, "no firmware loaded\n");
+		destroy_workqueue(rtwdev->txq_wq);
 		return ret;
 	}
 	rtw89_ser_init(rtwdev);