staging: rtl8192u: remove null check after call container_of()

container_of() will never return NULL, so remove useless code.
Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Link: https://lore.kernel.org/r/1652696533-18011-1-git-send-email-baihaowen@meizu.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c

@@ -1700,8 +1700,6 @@ static inline void ieee80211_sta_ps(struct work_struct *work)
 	unsigned long flags, flags2;
 
 	ieee = container_of(work, struct ieee80211_device, ps_task);
-	if (!ieee)
-		return;
 
 	spin_lock_irqsave(&ieee->lock, flags);