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/kp_imx6q_tpc_defconfig b/configs/kp_imx6q_tpc_defconfig
index 2484e91..72f7d21 100644
--- a/configs/kp_imx6q_tpc_defconfig
+++ b/configs/kp_imx6q_tpc_defconfig
@@ -42,6 +42,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="imx6q-kp"
 CONFIG_OF_SPL_REMOVE_PROPS="interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents interrupts dmas dma-names"
 CONFIG_ENV_IS_IN_MMC=y
+CONFIG_SYS_REDUNDAND_ENVIRONMENT=y
 # CONFIG_BLOCK_CACHE is not set
 CONFIG_SPL_CLK_IMX6Q=y
 CONFIG_CLK_IMX6Q=y