IB/core: Change ib_resolve_eth_dmac to use it in create AH

The function ib_resolve_eth_dmac() requires struct qp_attr * and
qp_attr_mask as parameters while the function might be useful to resolve
dmac for address handles. This patch changes the signature of the
function so it can be used in the flow of creating an address handle.

Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>