ib_response_mad only needs read access to the MAD header, not write access
to the entire mad struct, so replace struct ib_mad with const struct
ib_mad_hdr
Reviewed-By: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>