Staging: fix wlan-ng depends

drivers/built-in.o: In function `wlan_free_wiphy':
(.text+0x3f5eb5): undefined reference to `wiphy_unregister'
drivers/built-in.o: In function `wlan_free_wiphy':
(.text+0x3f5ec4): undefined reference to `wiphy_free'
drivers/built-in.o: In function `wlan_create_wiphy':
(.text+0x3f5f76): undefined reference to `wiphy_new'
drivers/built-in.o: In function `wlan_create_wiphy':
(.text+0x3f6024): undefined reference to `wiphy_register'
drivers/built-in.o: In function `prism2_roamed':
(.text+0x3f61f7): undefined reference to `cfg80211_roamed'
drivers/built-in.o: In function `prism2_disconnected':
(.text+0x3f6223): undefined reference to `cfg80211_disconnected'
drivers/built-in.o: In function `prism2_connect_result':
(.text+0x3f626d): undefined reference to `cfg80211_connect_result'
drivers/built-in.o: In function `prism2_connect':
(.text+0x3f62b6): undefined reference to `ieee80211_frequency_to_channel'
drivers/built-in.o: In function `prism2_scan':
(.text+0x3f6679): undefined reference to `ieee80211_frequency_to_channel'
drivers/built-in.o: In function `prism2_scan':
(.text+0x3f6873): undefined reference to `__ieee80211_get_channel'
drivers/built-in.o: In function `prism2_scan':
(.text+0x3f68cc): undefined reference to `cfg80211_inform_bss'
drivers/built-in.o: In function `prism2_scan':
(.text+0x3f6942): undefined reference to `cfg80211_scan_done'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/wlan-ng/Kconfig

 config PRISM2_USB
 	tristate "Prism2.5/3 USB driver"
-	depends on WLAN && USB
+	depends on WLAN && USB && CFG80211
 	select WIRELESS_EXT
 	select WEXT_PRIV
 	default n