uboot-envtools: fix fw_env.config for ox820/stg-212

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

package/boot/uboot-envtools/files/oxnas

@@ -14,10 +14,12 @@ board=$(board_name)
 
 case "$board" in
 "cloudengines,pogoplug"* | \
-"mitrastar,stg-212" | \
 "shuttle,kd20")
 	ubootenv_add_uci_config "/dev/mtd2" "0x0" "0x2000" "0x2000" "1"
 	;;
+"mitrastar,stg-212")
+	ubootenv_add_uci_config "/dev/mtd2" "0x0" "0x20000" "0x20000" "1"
+	;;
 esac
 
 config_load ubootenv