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/dra7xx_evm_defconfig b/configs/dra7xx_evm_defconfig
index a1a5dc5..cb2cdcb 100644
--- a/configs/dra7xx_evm_defconfig
+++ b/configs/dra7xx_evm_defconfig
@@ -46,6 +46,7 @@
 CONFIG_OF_SPL_REMOVE_PROPS="clocks clock-names interrupt-parent"
 # CONFIG_ENV_IS_IN_FAT is not set
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_ENV_VARS_UBOOT_RUNTIME_CONFIG=y
 CONFIG_DM=y
 CONFIG_SPL_DM=y