ramips: add support for the Asus RP-N53 in the "02_network" boot script

This patch adds a case for the Asus RP-N53 in the "02_network" boot script. Without this, the lan interface does not get configured on startup, effectively bricking the device.

Signed-off-by: Alberto Mattea <alberto@mattea.info>

SVN-Revision: 47345