ramips: Fix Hongdian H7920 v40 mac address
After extracting the EEPROMs of different devices, only the 0x4 address is unique.
Use the 0x4 address as the LAN address, and the LAN+1 address as the WAN address.
Signed-off-by: Coia Prant <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20256
(cherry picked from commit c907c7c9b3f0b66bbafc75a2ae1111fbf873a1c3)
Link: https://github.com/openwrt/openwrt/pull/20257
Signed-off-by: Hauke Mehrtens <[email protected]>