ramips: ArcherC50v1: fix wlan2g MAC address
By default the wlan eprom contains the generic ralink MAC which is not
the vendor (TP-Link) one. Based on OFW bootlog, it appears that addresses
are decremented from the ethernet MAC.
This patch fixes the MAC address for wlan2g in line with OFW.
Signed-off-by: Thibaut VARENE <[email protected]>