staging: wilc1000: fixes variable dereferenced before check

This patch fixes the warning reported by smatch.
 - wilc_wlan_get_firmware() warn: variable dereferenced before check 'vif'
 - wilc_set_multicast_list() warn: variable dereferenced before check 'dev'

Just delete them and no need add null check since they are net_device from
ndo_set_rx_mode of net_device_ops and vif of netdev_priv.
Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wilc1000/linux_wlan.c

@@ -397,9 +397,6 @@ int wilc_wlan_get_firmware(struct net_device *dev)
 
 	netdev_info(dev, "loading firmware %s\n", firmware);
 
-	if (!vif)
-		goto _fail_;
-
 	if (!(&vif->ndev->dev))
 		goto _fail_;
 
@@ -1017,9 +1014,6 @@ static void wilc_set_multicast_list(struct net_device *dev)
 	vif = netdev_priv(dev);
 	hif_drv = (struct host_if_drv *)priv->hif_drv;
 
-	if (!dev)
-		return;
-
 	if (dev->flags & IFF_PROMISC)
 		return;