mwifiex: fix mwifiex_hard_start_xmit()'s return type

The method ndo_start_xmit() is defined as returning an 'netdev_tx_t',
which is a typedef for an enum type, but the implementation in this
driver returns an 'int'.

Fix this by returning 'netdev_tx_t' in this driver too.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/main.c

@@ -858,7 +858,7 @@ mwifiex_clone_skb_for_tx_status(struct mwifiex_private *priv,
 /*
  * CFG802.11 network device handler for data transmission.
  */
-static int
+static netdev_tx_t
 mwifiex_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct mwifiex_private *priv = mwifiex_netdev_get_priv(dev);