RDMA/rxe: Implement synchronous prefetch for ODP MRs

Minimal implementation of ibv_advise_mr(3) requires synchronous calls being
successful with the IBV_ADVISE_MR_FLAG_FLUSH flag. Asynchronous requests,
which are best-effort, will be supported subsequently.

Signed-off-by: Daisuke Matsuda <dskmtsd@gmail.com>
Link: https://patch.msgid.link/20250522111955.3227-2-dskmtsd@gmail.com


Reviewed-by: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Leon Romanovsky <leon@kernel.org>