Remove wrapper rtw_udelay_os()

This wrapper is a simple call to udelay(). Remove it.

Link: https://lore.kernel.org/r/20210805192644.15978-4-Larry.Finger@lwfinger.net

core/rtw_xmit.c

@@ -4418,7 +4418,7 @@ s32 rtw_monitor_xmit_entry(struct sk_buff *skb, struct net_device *ndev)
 #endif
 	pmgntframe = alloc_mgtxmitframe(pxmitpriv);
 	if (pmgntframe == NULL) {
-		rtw_udelay_os(500);
+		udelay(500);
 		goto fail;
 	}