wifi: rtw88: add missing destroy_workqueue() on error path in rtw_core_init()

Add the missing destroy_workqueue() before return from rtw_core_init()
in error path.

Fixes: fe101716 ("rtw88: replace tx tasklet with work queue")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220826023817.3908255-1-yangyingliang@huawei.com