defconfigs: Migrate CONFIG_SYS_REDUNDAND_ENVIRONMENT

Move this symbol to Kconfig.  As part of this we can drop a UBI-specific
symbol that was a stop-gap for not having this particular symbol in
Kconfig.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/MPC8313ERDB_NAND_33_defconfig b/configs/MPC8313ERDB_NAND_33_defconfig
index 4c30f75..a3c8117 100644
--- a/configs/MPC8313ERDB_NAND_33_defconfig
+++ b/configs/MPC8313ERDB_NAND_33_defconfig
@@ -150,6 +150,7 @@
 CONFIG_MTDPARTS_DEFAULT="mtdparts=e2800000.flash:512k(uboot),128k(env),6m@1m(kernel),-(fs)"
 # CONFIG_ENV_IS_IN_FLASH is not set
 CONFIG_ENV_IS_IN_NAND=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 # CONFIG_MMC is not set
 CONFIG_MTD_NOR_FLASH=y
 CONFIG_FLASH_CFI_DRIVER=y