net: ethernet: adi: adin1110: use eth_broadcast_addr() to assign broadcast address

Use eth_broadcast_addr() to assign broadcast address instead
of memset().

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>