wireguard: selftests: remove old conntrack kconfig value

On recent kernels, this config symbol is no longer used.
Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Fixes: e7096c13 ("net: WireGuard secure network tunnel")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/wireguard/qemu/kernel.config

@@ -19,7 +19,6 @@ CONFIG_NETFILTER_XTABLES=y
 CONFIG_NETFILTER_XT_NAT=y
 CONFIG_NETFILTER_XT_MATCH_LENGTH=y
 CONFIG_NETFILTER_XT_MARK=y
-CONFIG_NF_CONNTRACK_IPV4=y
 CONFIG_NF_NAT_IPV4=y
 CONFIG_IP_NF_IPTABLES=y
 CONFIG_IP_NF_FILTER=y