ar71xx: rw2458n - Use eeprom (art) from wifi card

Use eeprom (art) from included wifi card, not hard coded in flash.

Signed-off-by: Cezary Jackiewicz <cezary.jackiewicz@gmail.com>
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@36037 3c298f89-4303-0410-b956-a3cf2f4a3e73