net/mlx5: HWS, Create STEs directly from matcher

net/mlx5: HWS, Create STEs directly from matcher

Matchers were using the pool abstraction solely as a convenience
to allocate two STE ranges. The pool's core functionality, that
of allocating individual items from the range, was unused.
Matchers rely either on the hardware to hash rules into a table,
or on a user-provided index.

Remove the STE pool from the matcher and allocate the STE ranges
manually instead.

Signed-off-by: Vlad Dogaru <vdogaru@nvidia.com>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Mark Bloch <mbloch@nvidia.com>
Link: https://patch.msgid.link/20250703185431.445571-6-mbloch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>