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/edison_defconfig b/configs/edison_defconfig
index 553b22c..672b2bb 100644
--- a/configs/edison_defconfig
+++ b/configs/edison_defconfig
@@ -28,6 +28,7 @@
 CONFIG_CMD_FS_GENERIC=y
 CONFIG_DEFAULT_DEVICE_TREE="edison"
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_CPU=y
 CONFIG_DFU_MMC=y
 CONFIG_DFU_RAM=y