net/arp: fix the problem of arp notify and flood arp sending

when a arp response reached, it should notify all tasks waiting the address. if the address is unreachable, do not send arp request to prevent arp flooding.

Signed-off-by: wenquan1 <wenquan1@xiaomi.com>

net/arp/arp_notify.c

@@ -205,7 +205,6 @@ void arp_notify(in_addr_t ipaddr)
 
           curr->nt_result = OK;
           nxsem_post(&curr->nt_sem);
-          break;
         }
     }
 

net/arp/arp_out.c

@@ -253,7 +253,7 @@ void arp_out(FAR struct net_driver_s *dev)
     {
       /* No send ARP if the interface forbidden */
 
-      if (IFF_IS_NOARP(dev->d_flags))
+      if (IFF_IS_NOARP(dev->d_flags) || ret == -ENETUNREACH)
         {
           ninfo("ARP not supported on %s, no send!\n", dev->d_ifname);
           dev->d_len = 0;