xilinx: Enable redundant variable handling

Enable this feature by default to be able to work with env import/export
commands which are done in this slightly changed variable format (There is
addtional flag fields in variable file which is changing CRC calculation).

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/configs/microblaze-generic_defconfig b/configs/microblaze-generic_defconfig
index 761cc65..245763b 100644
--- a/configs/microblaze-generic_defconfig
+++ b/configs/microblaze-generic_defconfig
@@ -40,6 +40,7 @@
 CONFIG_CMD_JFFS2=y
 CONFIG_SPL_OF_CONTROL=y
 CONFIG_OF_EMBED=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_NET_RANDOM_ETHADDR=y
 CONFIG_NETCONSOLE=y
 CONFIG_SPL_DM=y