staging: rtl8723bs: fix rtw_cfg80211_monitor_if_xmit_entry()'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>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c

@@ -2472,7 +2472,7 @@ static int rtw_cfg80211_monitor_if_close(struct net_device *ndev)
 	return ret;
 }
 
-static int rtw_cfg80211_monitor_if_xmit_entry(struct sk_buff *skb, struct net_device *ndev)
+static netdev_tx_t rtw_cfg80211_monitor_if_xmit_entry(struct sk_buff *skb, struct net_device *ndev)
 {
 	int ret = 0;
 	int rtap_len;