ath: use menuconfig to put ath stuff in its own page

Signed-off-by: NLuis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/Kconfig

-config ATH_COMMON
+menuconfig ATH_COMMON
 	tristate "Atheros Wireless Cards"
 	depends on WLAN_80211
 	depends on CFG80211