net/ibmveth: fix panic in probe

netdev->dev_addr changed from being an array to being a pointer, so we
should not take its address for memcpy().

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>