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/vining_2000_defconfig b/configs/vining_2000_defconfig
index b007a76..0eefc76 100644
--- a/configs/vining_2000_defconfig
+++ b/configs/vining_2000_defconfig
@@ -35,6 +35,7 @@
 CONFIG_EFI_PARTITION=y
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="imx6sx-softing-vining-2000"
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
 CONFIG_DM_GPIO=y
 CONFIG_DM_MMC=y