[platform-netif] disable icmp echo (#3590)

src/posix/platform/netif.cpp

@@ -52,6 +52,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <openthread/icmp6.h>
 #include <openthread/instance.h>
 #include <openthread/ip6.h>
 #include <openthread/message.h>
@@ -392,6 +393,8 @@ void platformNetifInit(otInstance *aInstance)
     sNetlinkFd = socket(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE);
     VerifyOrExit(sNetlinkFd > 0);
 
+    otIcmp6SetEchoMode(aInstance, OT_ICMP6_ECHO_HANDLER_DISABLED);
+
     {
         struct sockaddr_nl sa;