RDMA/mlx5: Fix mlx5 rates to IB rates map

RDMA/mlx5: Fix mlx5 rates to IB rates map

[ Upstream commit 6fe6e568639859db960c8fcef19a2ece1c2d7eae ]

Correct the map between mlx5 rates and corresponding ib rates, as they
don't always have a fixed offset between them.

Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Link: https://lore.kernel.org/r/20210304124517.1100608-4-leon@kernel.org
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Reviewed-by: Maor Gottlieb <maorg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>