net/mlx5e: Fix maxrate wraparound in threshold between units

net/mlx5e: Fix maxrate wraparound in threshold between units

The previous calculation used roundup() which caused an overflow for
rates between 25.5Gbps and 26Gbps.
For example, a rate of 25.6Gbps would result in using 100Mbps units with
value of 256, which would overflow the 8 bits field.

Simplify the upper_limit_mbps calculation by removing the
unnecessary roundup, and adjust the comparison to use <= to correctly
handle the boundary condition.

Fixes: d8880795dabf ("net/mlx5e: Implement DCBNL IEEE max rate")
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Nimrod Oren <noren@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1762681073-1084058-4-git-send-email-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>