rt2x00: Fix sparse warning on nested container_of()

Sparse produces warnings about nested contain_of() statements,
this means that lines like:
	interface_to_usbdev(to_usb_interface(rt2x00dev->dev));
will upset sparse.
Add a new macro to rt2x00usb.h which will convert to device
structure to the usb_device pointer in 2 steps to prevent this
sparse warning.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 2 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index 6b6e7b93d2ad..d0958008c013 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -1672,8 +1672,7 @@ static int rt2500usb_probe_hw(struct rt2x00_dev *rt2x00dev)
 static int rt2500usb_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
         struct rt2x00_dev *rt2x00dev = hw->priv;
-        struct usb_device *usb_dev =
-                interface_to_usbdev(to_usb_interface(rt2x00dev->dev));
+        struct usb_device *usb_dev = to_usb_device_intf(rt2x00dev->dev);
         struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
         struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
         struct queue_entry_priv_usb_bcn *bcn_priv;