There's no valid mac address for the second band in the eeprom.
The vendor fw uses 2.4G mac + 4 as the mac for 5G radio.
Do the same in our firmware.
Fixes: 23be410b3d ("ramips: add support for TOTOLINK X5000R")
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
(cherry picked from commit 2126325400)