RDMA/rxe: Delete _locked() APIs for pool objects

Since caller managed locks for indexed objects are no longer used these
APIs are deleted.

Link: https://lore.kernel.org/r/20220304000808.225811-5-rpearsonhpe@gmail.com


Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>