RDMA/mad: Delete duplicated init_query_mad functions

Several drivers used same function to initialize query MAD,
so move that function to global header file.

Link: https://lore.kernel.org/r/af6f35c590ff5ef56d0137351b8b295af0f7c13c.1641369858.git.leonro@nvidia.com


Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>