There is no need to manually write same callbacks, automatically generate
them using C-macro language.

This macro is going to be extended to generate doit callbacks too, so use
general name for this macro.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>