samples/bpf: fix bpf tunnel cleanup

test_tunnel_bpf.sh fails to remove the vxlan11 tunnel device, causing the
next geneve tunnelling test case fails.  In addition, the geneve reserved bit
in tcbpf2_kern.c should be zero, according to the RFC.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/samples/bpf/test_tunnel_bpf.sh b/samples/bpf/test_tunnel_bpf.sh
index 1ff634f..a70d2ea 100755
--- a/samples/bpf/test_tunnel_bpf.sh
+++ b/samples/bpf/test_tunnel_bpf.sh
@@ -149,6 +149,7 @@
 	ip link del veth1
 	ip link del ipip11
 	ip link del gretap11
+	ip link del vxlan11
 	ip link del geneve11
 	pkill tcpdump
 	pkill cat