clearfog: Support updating with RAUC

This needs a few changes to the host:

- `mke2fs` is required to re-create the filesystem
- `unsquashfs` is needed for working `rauc info`

Change-Id: I036304286db3fb456c366c65704923f5d7321917
diff --git a/board/czechlight/common/busybox-config b/board/czechlight/common/busybox-config
index b19cfd3..af0efe0 100644
--- a/board/czechlight/common/busybox-config
+++ b/board/czechlight/common/busybox-config
@@ -4,3 +4,4 @@
 
 # rauc
 CONFIG_FEATURE_TAR_AUTODETECT=y
+CONFIG_FEATURE_SEAMLESS_XZ=y