Staging: wlan-ng: fix comparison to NULL issue.

This patch fixes comparison to NULL could be written "wlandev" found
by checkpatch.pl tool.
Signed-off-by: Kevin McKinney <klmckinney1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wlan-ng/prism2usb.c

@@ -137,7 +137,7 @@ static void prism2sta_disconnect_usb(struct usb_interface *interface)
 	wlandevice_t *wlandev;
 
 	wlandev = (wlandevice_t *)usb_get_intfdata(interface);
-	if (wlandev != NULL) {
+	if (wlandev) {
 		LIST_HEAD(cleanlist);
 		hfa384x_usbctlx_t *ctlx, *temp;
 		unsigned long flags;