* Refactor MR registration and cleanup, and fix reg_pages accounting.
* Create a work queue to handle page fault events in a kthread context.
* Register a fault handler to get events from the core for each QP.

The registered fault handler is empty in this patch, and only a later
patch implements it.
Signed-off-by: NSagi Grimberg <sagig@mellanox.com>
Signed-off-by: NShachar Raindel <raindel@mellanox.com>
Signed-off-by: NHaggai Eran <haggaie@mellanox.com>
Signed-off-by: NRoland Dreier <roland@purestorage.com>