qed: Replace memset with eth_zero_addr

Use eth_zero_addr to assign zero address to the given address array
instead of memset when the second argument in memset is address
of zero. Also, it makes the code clearer

Signed-off-by: Shyam Saini <mayhs11saini@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>