staging: r8712u: Fix Smatch warning

The patch 2080913e: "staging: r8712u: Fix regression caused by
commit 8c213fa5" from Feb 25, 2012, leads to the following Smatch
complaint:

drivers/staging/rtl8712/usb_intf.c:629 r871xu_dev_remove()
	 warn: variable dereferenced before check 'padapter' (see line 625)

The fix is to move the new statements inside the block where padapter
is not NULL.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8712/usb_intf.c

@@ -620,12 +620,12 @@ static void r871xu_dev_remove(struct usb_interface *pusb_intf)
 	struct _adapter *padapter = netdev_priv(pnetdev);
 	struct usb_device *udev = interface_to_usbdev(pusb_intf);
 
-	if (padapter->fw_found)
-		release_firmware(padapter->fw);
-	/* never exit with a firmware callback pending */
-	wait_for_completion(&padapter->rtl8712_fw_ready);
 	usb_set_intfdata(pusb_intf, NULL);
 	if (padapter) {
+		if (padapter->fw_found)
+			release_firmware(padapter->fw);
+		/* never exit with a firmware callback pending */
+		wait_for_completion(&padapter->rtl8712_fw_ready);
 		if (drvpriv.drv_registered == true)
 			padapter->bSurpriseRemoved = true;
 		if (pnetdev != NULL) {