Add squashfs-XZ.

XZ provides vastly better compression in our
rootfs, nearly 30% better compared with gzip.

Change-Id: I80e00e470593bb805ef42c6048218671ffdc2899
diff --git a/arch/arm/configs/gfrg200_defconfig b/arch/arm/configs/gfrg200_defconfig
index 983573c..79456e2 100644
--- a/arch/arm/configs/gfrg200_defconfig
+++ b/arch/arm/configs/gfrg200_defconfig
@@ -281,6 +281,7 @@
 CONFIG_UBIFS_FS=y
 CONFIG_UBIFS_FS_DEBUG=y
 CONFIG_SQUASHFS=y
+CONFIG_SQUASHFS_XZ=y
 CONFIG_SQUASHFS_EMBEDDED=y
 CONFIG_NFS_FS=y
 CONFIG_NFS_V3=y