configs: clearfog: enable random random MAC address

This makes the network devices usable when booting a blank board over
UART, with no pre-configured MAC address stored in the environment area.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/configs/clearfog_defconfig b/configs/clearfog_defconfig
index 2359ad2..ff954c7 100644
--- a/configs/clearfog_defconfig
+++ b/configs/clearfog_defconfig
@@ -30,6 +30,7 @@
 CONFIG_CMD_TIME=y
 # CONFIG_SPL_PARTITION_UUIDS is not set
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_SPL_OF_TRANSLATE=y
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_SDMA=y