IB/mlx4: Change alias guids default to be host assigned

Change the default mode to be HOST assigned instead of SM assigned. This is
the expected operational mode, because it doesn't depend on SM availability.

As PF generates random GUIDs as the initial admin values, this gives
out of the box experience.

Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>