Implement velia-firewall

Change-Id: I228f15fca7ed784bf1043e4074cf8e76fcd6a842
diff --git a/configs/czechlight_clearfog_defconfig b/configs/czechlight_clearfog_defconfig
index e894eac..316a7ab 100644
--- a/configs/czechlight_clearfog_defconfig
+++ b/configs/czechlight_clearfog_defconfig
@@ -60,6 +60,7 @@
 BR2_PACKAGE_ETHTOOL=y
 BR2_PACKAGE_IPROUTE2=y
 BR2_PACKAGE_NETCONF_CLI=y
+BR2_PACKAGE_NFTABLES=y
 BR2_PACKAGE_OPENSSH=y
 BR2_PACKAGE_TCPDUMP=y
 BR2_PACKAGE_BASH=y