ar71xx: use a common naming scheme for LEDS on wnr2000-v4

It is common that the router provider be used rather than product name.
One can see this in target/linux/ar71xx/base-files/etc/uci-defaults/01_leds

Signed-off-by: Michael J. Bazzinotti <mbazzinotti@gmail.com>

SVN-Revision: 45630