mlx4_core: Add a way to set the "collapsed" CQ flag

Extend the mlx4_cq_resize() API with a way to set the "collapsed" flag
for the CQ being created.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>