ath79: wndap360: switch MACs to newer firmware

ath79: wndap360: switch MACs to newer firmware

Original ar71xx has this setup:

define WNDAP360_WMAC0_MAC_OFFSET               0x120c
define WNDAP360_WMAC1_MAC_OFFSET               0x520c

/* Reusing wifi MAC with offset of 1 as eth0 MAC */
ath79_init_mac(ath79_eth0_data.mac_addr,
               art + WNDAP360_WMAC0_MAC_OFFSET, 1);

ap94_pci_init(art + WNDAP360_CALDATA0_OFFSET,
              art + WNDAP360_WMAC0_MAC_OFFSET,
              art + WNDAP360_CALDATA1_OFFSET,
              art + WNDAP360_WMAC1_MAC_OFFSET);

The ath79 port made a questionable change for eth0 being just art with
no offset. That MAC ends up being the OUI for Atheros.

WNDAP360_WMAC1_MAC_OFFSET is the same as WNDAP360_WMAC0_MAC_OFFSET
except with the first hex value being subtracted by 2, which is not a
valid OUI.

And newer Netgear firmware seems to assign differently as well,
art_120C as a base and the others incremented by 0x8.

Switch the assignment to the latest firmware and add label-mac-device to
document that the first Wi-FI MAC address is printed on the device.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/22895
Signed-off-by: Jonas Jelonek <jelonek.jonas@gmail.com>