staging: vt6656: set usb_set_intfdata on driver fail.

intfdata will contain stale pointer when the device is detached after
failed initialization when referenced in vt6656_disconnect

Provide driver access to it here and NULL it.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/6de448d7-d833-ef2e-dd7b-3ef9992fee0e@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vt6656/device.h

@@ -259,6 +259,7 @@ struct vnt_private {
 	u8 mac_hw;
 	/* netdev */
 	struct usb_device *usb;
+	struct usb_interface *intf;
 
 	u64 tsf_time;
 	u8 rx_rate;

drivers/staging/vt6656/main_usb.c

@@ -992,6 +992,7 @@ vt6656_probe(struct usb_interface *intf, const struct usb_device_id *id)
 	priv = hw->priv;
 	priv->hw = hw;
 	priv->usb = udev;
+	priv->intf = intf;
 
 	vnt_set_options(priv);
 

drivers/staging/vt6656/wcmd.c

@@ -99,6 +99,7 @@ void vnt_run_command(struct work_struct *work)
 		if (vnt_init(priv)) {
 			/* If fail all ends TODO retry */
 			dev_err(&priv->usb->dev, "failed to start\n");
+			usb_set_intfdata(priv->intf, NULL);
 			ieee80211_free_hw(priv->hw);
 			return;
 		}