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/theadorable-x86-conga-qa3-e3845-pcie-x4_defconfig b/configs/theadorable-x86-conga-qa3-e3845-pcie-x4_defconfig
index 770804f..d0e6464 100644
--- a/configs/theadorable-x86-conga-qa3-e3845-pcie-x4_defconfig
+++ b/configs/theadorable-x86-conga-qa3-e3845-pcie-x4_defconfig
@@ -45,6 +45,7 @@
 CONFIG_AMIGA_PARTITION=y
 CONFIG_EFI_PARTITION=y
 CONFIG_DEFAULT_DEVICE_TREE="conga-qeval20-qa3-e3845"
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 CONFIG_REGMAP=y
 CONFIG_SYSCON=y
 CONFIG_CPU=y