armv8: ls2085a: Add support of random MAC address

Add support of setting RANDOM MAC address if env variable not available.

Signed-off-by: Prabhakar Kushwaha <prabhakar@freescale.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: York Sun <yorksun@freescale.com>
diff --git a/configs/ls2085a_simu_defconfig b/configs/ls2085a_simu_defconfig
index de9776d..9d04218 100644
--- a/configs/ls2085a_simu_defconfig
+++ b/configs/ls2085a_simu_defconfig
@@ -12,3 +12,4 @@
 # CONFIG_CMD_SETEXPR is not set
 # CONFIG_CMD_NFS is not set
 # CONFIG_CMD_MISC is not set
+CONFIG_NET_RANDOM_ETHADDR=y