RDMA/mlx5: Add implementation for ufile_hw_cleanup device operation

Implement the device API for ufile_hw_cleanup operation, which
iterates over the ufile uobjects lists, and attempts to destroy
DevX QPs, by issuing up to 8 commands in parallel.

This function is responsible only for cleaning the FW resources of the
QP, and doesn't necessarily cleanup all of its resources.
Hence the normal serialized cleanup flow is still executed after it
in __uverbs_cleanup_ufile() to cleanup the remaining resources and
handle the cleanup of SW objects.

In order to avoid double cleanup for the FW resources, new DevX flag
was added DEVX_OBJ_FLAGS_HW_FREED, which marks the object's FW resources
as already freed.

Since QP destruction is the most time-consuming operation in FW,
parallelizing it reduces the cleanup time of applications that use
DevX QPs.

Signed-off-by: Patrisious Haddad <phaddad@nvidia.com>
Link: https://patch.msgid.link/2f82675d0412542cba1c47a6b86f589521ae41e1.1730373303.git.leon@kernel.org


Signed-off-by: Leon Romanovsky <leon@kernel.org>