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>
diff --git a/configs/ls1021atsn_sdcard_defconfig b/configs/ls1021atsn_sdcard_defconfig
index da379a5..506a337 100644
--- a/configs/ls1021atsn_sdcard_defconfig
+++ b/configs/ls1021atsn_sdcard_defconfig
@@ -66,6 +66,7 @@
 CONFIG_PHY_ATHEROS=y
 CONFIG_PHY_BROADCOM=y
 CONFIG_PHY_FIXED=y
+CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_DM_ETH=y
 CONFIG_DM_MDIO=y
 CONFIG_DM_DSA=y