arm: mvebu: defconfig: espressobin: enable NET_RANDOM_ETHADDR

The hardware does not provide a MAC address. Enable this so that
network access works with just the default environment.

Signed-off-by: Andre Heider <a.heider@gmail.com>
Acked-by: Konstantin Porotchkin <kostap@marvell.com>
diff --git a/configs/mvebu_espressobin-88f3720_defconfig b/configs/mvebu_espressobin-88f3720_defconfig
index 7aabbba..5e9fcd1 100644
--- a/configs/mvebu_espressobin-88f3720_defconfig
+++ b/configs/mvebu_espressobin-88f3720_defconfig
@@ -84,3 +84,4 @@
 CONFIG_USB_ETHER_SMSC95XX=y
 CONFIG_SHA1=y
 CONFIG_SHA256=y
+CONFIG_NET_RANDOM_ETHADDR=y