RDMA/core: Save kernel caller name when creating PD and CQ objects

The KBUILD_MODNAME variable contains the module name and it is known for
kernel users during compilation, so let's reuse it to track the owners.

Followup patches will store this for resource tracking.

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