riscv: dts: microchip: Use 'local-mac-address' for emac1
Per the DT spec, 'local-mac-address' is used to specify MAC address
that was assigned to the network device, while 'mac-address' is used
to specify the MAC address that was last used by the boot program,
and shall be used only if the value differs from 'local-mac-address'
property value.