ARM: dts: NSP: MX6X: get mac-address from eeprom

The MAC address on the MX64/MX65 series is located on the AT24 EEPROM.
This is the same as other Meraki devices such as the MR32 [1].

[1] https://lore.kernel.org/linux-arm-kernel/fa8271d02ef74a687f365cebe5c55ec846963ab7.1631986106.git.chunkeey@gmail.com/



Signed-off-by: Matthew Hagan <mnhagan88@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>