IB/mlx4: Move mlx4_uverbs_ex_query_device_resp to include/uapi/

This struct is involved in the user API for mlx4 and should not be hidden
inside a driver header file.

Fixes: 09d208b2

 ("IB/mlx4: Add report for RSS capabilities by vendor channel")
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>