net/mlx5: Remove from FPGA IFC file not-needed definitions

Move IP layout bits definitions to be close to the place that actually
uses it, together with removal extra defines that not in-use.

Reviewed-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>