rtl8180: Fix to add STA mode

To be compatible with mac80211 following "mac80211: only create
default STA interface if supported", rtl8180 needs to set
NL80211_IFTYPE_STATION in interface_modes.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Fabio Rossi <rossi.f@inwind.it>
Tested-by: Piter PUNK <piterpunk@unitednerds.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rtl818x/rtl8180_dev.c

@@ -897,6 +897,7 @@ static int __devinit rtl8180_probe(struct pci_dev *pdev,
 	dev->flags = IEEE80211_HW_HOST_BROADCAST_PS_BUFFERING |
 		     IEEE80211_HW_RX_INCLUDES_FCS |
 		     IEEE80211_HW_SIGNAL_UNSPEC;
+	dev->wiphy->interface_modes = BIT(NL80211_IFTYPE_STATION);
 	dev->queues = 1;
 	dev->max_signal = 65;