net/mlx5: HWS, handle returned error value in pool alloc

Handle all negative return values as errors, not just -1.
The code previously treated -ENOMEM (and potentially other negative
values) as valid segment numbers, leading to incorrect behavior.
This fix ensures that any negative return value is treated as an error.

Signed-off-by: Vlad Dogaru <vdogaru@nvidia.com>
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Mark Bloch <mbloch@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20250102181415.1477316-13-tariqt@nvidia.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>