Implement velia-firewall

Change-Id: I228f15fca7ed784bf1043e4074cf8e76fcd6a842
diff --git a/board/czechlight/common/linux.fragment b/board/czechlight/common/linux.fragment
index 2181c3b..2f478df 100644
--- a/board/czechlight/common/linux.fragment
+++ b/board/czechlight/common/linux.fragment
@@ -101,3 +101,7 @@
 CONFIG_IKCONFIG_PROC=y
 CONFIG_SCHEDSTATS=y
 CONFIG_AUDIT=y
+CONFIG_NETFILTER=y
+CONFIG_NF_CONNTRACK=y
+CONFIG_NF_TABLES=y
+CONFIG_NFT_CT=y