Fix vpp crash when create vxlan/vxlan-gpe/geneve/gtpu tunnel with 0.0.0.0 dst ip in debug build. The ASSERT should be move out of fib_prefix_from_ip46_addr, which may be called when create vxlan/vxlan-gpe/geneve/gtpu tunnel with 0.0.0.0 dst ip. How to reproduce: 1. build debug vpp and run vpp 2. create vxlan t src 192.168.0.2 dst 0.0.0.0 vni 1 instance 1 create vxlan-gpe tunnel local 192.168.0.2 remote 0.0.0.0 vni 1 create geneve tunnel local 192.168.0.2 remote 0.0.0.0 vni 1 create gtpu tunnel src 192.168.0.2 dst 0.0.0.0 teid 1 Type: fix Change-Id: I19972f6af588f4ff7fd17de1b16b9301e43d596f Signed-off-by: Huawei LI <lihuawei_zzu@163.com>