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/kmnusa_defconfig b/configs/kmnusa_defconfig
index bca8e9b..15cb7d1 100644
--- a/configs/kmnusa_defconfig
+++ b/configs/kmnusa_defconfig
@@ -34,6 +34,7 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="kirkwood-km_kirkwood"
 CONFIG_ENV_IS_IN_SPI_FLASH=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_BOOTCOUNT_LIMIT=y
 CONFIG_BOOTCOUNT_RAM=y
 CONFIG_BOOTCOUNT_BOOTLIMIT=3