configs: ls1021a-tsn: enable the generation of random Ethernet MAC addresses

Don't fail when booting a board with an empty EEPROM for MAC addresses.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>