[lwip-users] Gratuitous ARP Target Hardware Address

[HM2]

This is probably nit picky, but I think the Target Hardware Address should
be set to the FF... broadcast value, rather than Zero.  This is in Etharp.c
in the function etharp_request().  &ethzero is used where I think it should
be &ethbroadcast.  In the other examples and doc I always see  FF... used
for this value.

Regards,  Chris.