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/am335x_igep003x_defconfig b/configs/am335x_igep003x_defconfig
index 8ed52a5..92a550d 100644
--- a/configs/am335x_igep003x_defconfig
+++ b/configs/am335x_igep003x_defconfig
@@ -56,6 +56,7 @@
 CONFIG_OF_CONTROL=y
 CONFIG_DEFAULT_DEVICE_TREE="am335x-base0033"
 CONFIG_ENV_IS_IN_UBI=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_ENV_UBI_PART="UBI"
 CONFIG_ENV_UBI_VOLUME="config"
 CONFIG_ENV_UBI_VOLUME_REDUND="config_r"