net/mlx5: Add IRQ vector to CPU lookup function

net/mlx5: Add IRQ vector to CPU lookup function

Currently, once driver load completes, IRQ requests were performed for all
vectors. However, as we move to support dynamic creation of EQs, this will
not be the case as some IRQs will not exist at this stage. Thus, in such
case, use the default CPU to IRQ mapping which is the serial mapping based
on IRQ vector index. Meaning, the n'th vector gets mapped to the n'th CPU.

Introduce an API function mlx5_comp_vector_cpu() that takes an IRQ index and
provides the corresponding CPU mapping. It utilizes the existing IRQ
affinity if defined, or resorts to the default serialized CPU mapping
otherwise.

Signed-off-by: Maher Sanalla <msanalla@nvidia.com>
Reviewed-by: Shay Drory <shayd@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>