net/mlx4: Remove unused #define MAX_MSIX_P_PORT

All usages of the definition MAX_MSIX_P_PORT were removed.
It's not in use anymore. Remove it.

Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Reviewed-by: Moshe Shemesh <moshe@mellanox.com>
Link: https://lore.kernel.org/r/20201206091254.12476-1-tariqt@nvidia.com


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