IB/IPoIB: Support acceleration options callbacks

IPoIB driver now uses the new set of callback functions.

If the hardware provider supports the new ipoib_options implementation,
the driver uses the callbacks in its data path flows, otherwise it uses the
driver default implementation for all data flows in its code.

The default implementation wasn't change and it is exactly as it was before
introduction of acceleration support.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>