rndis_wlan: handle NL80211_AUTHTYPE_AUTOMATIC

rndis_wlan didn't know about NL80211_AUTHTYPE_AUTOMATIC and simple
setup with 'iwconfig wlan essid no-encrypt' would fail (ENOSUPP).

v2: use NDIS_80211_AUTH_AUTO_SWITCH instead of _OPEN.
    This will make device try shared key auth first, then open.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rndis_wlan.c

@@ -1072,6 +1072,8 @@ static int set_auth_mode(struct usbnet *usbdev, u32 wpa_version,
 		auth_mode = NDIS_80211_AUTH_SHARED;
 	else if (auth_type == NL80211_AUTHTYPE_OPEN_SYSTEM)
 		auth_mode = NDIS_80211_AUTH_OPEN;
+	else if (auth_type == NL80211_AUTHTYPE_AUTOMATIC)
+		auth_mode = NDIS_80211_AUTH_AUTO_SWITCH;
 	else
 		return -ENOTSUPP;