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/smartweb_defconfig b/configs/smartweb_defconfig
index 9e73051..b585a9f 100644
--- a/configs/smartweb_defconfig
+++ b/configs/smartweb_defconfig
@@ -43,6 +43,7 @@
 CONFIG_OF_EMBED=y
 CONFIG_DEFAULT_DEVICE_TREE="at91sam9260-smartweb"
 CONFIG_ENV_IS_IN_NAND=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_CLK=y
 CONFIG_CLK_AT91=y
 CONFIG_DFU_NAND=y