RDMA/rxe: Remove save/rollback_state in rxe_requester

RDMA/rxe: Remove save/rollback_state in rxe_requester

Now that req.task and comp.task are merged it is no longer necessary to
call save_state() before calling rxe_xmit_pkt() and rollback_state() if
rxe_xmit_pkt() fails. This was done originally to prevent races between
rxe_completer() and rxe_requester() which now cannot happen.

Link: https://lore.kernel.org/r/20240329145513.35381-8-rpearsonhpe@gmail.com
Signed-off-by: Bob Pearson <rpearsonhpe@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>