Pass actual capacity of created SRQ back to userspace, so that
userspace can report accurate capacities.  This requires an ABI bump,
to change struct ib_uverbs_create_srq_resp.
Signed-off-by: NDotan Barak <dotanb@mellanox.co.il>
Signed-off-by: NRoland Dreier <rolandd@cisco.com>