mediatek: fix MAC address assignment for ZBT Z8102AX V2

mediatek: fix MAC address assignment for ZBT Z8102AX V2

label: f8:5e:3c:99:95:c0

wifi-2.4G f8 5e 3c 99 95 be
wifi-5.8G f8 5e 3c 99 95 bf
eth0-lan  f8 5e 3c 99 95 c0
eth1-wan  f8 5e 3c 99 95 c1

:~# hexdump -C /dev/mtd2 | more
00000000  81 79 00 00 f8 5e 3c 99  95 be f8 5e 3c 99 95 bf  |.y...^<....^<...|
00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
00000020  00 00 00 00 f8 5e 3c 99  95 c1 f8 5e 3c 99 95 c0  |.....^<....^<...|
00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|

Signed-off-by: Xiao Qian <qxooqx@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/23016
Signed-off-by: Robert Marko <robimarko@gmail.com>