RDMA/mlx5: Fix udata response upon SRQ creation

Fix udata response upon SRQ creation to use the UAPI structure (i.e.
mlx5_ib_create_srq_resp). It did not zero the reserved field in userspace.

Fixes: e126ba97 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Link: https://lore.kernel.org/r/20200406173540.1466477-1-leon@kernel.org


Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>