Atheros Kconfig needs to be dependent on WLAN_80211

Atheros top level menu needs a "depends WLAN_80211" to properly indent
within menuconfig and xconfig interfaces.

This is purely a visual issue but it effects all subsequent drivers.
The issue is the top level menu does not include a dependency on
WLAN_80211 so within the tree structure, Atheros is at the same level as
WLAN_80211 but when WLAN_80211 collapsed, the menu disappears along with
all subsequent drives, so it is really a subordinate.

Signed-off-by: Jay Sternberg <jay.e.sternberg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>