i2c: tegra: Use separate variables for fast and fastplus

i2c: tegra: Use separate variables for fast and fastplus

The current implementation uses a single value of THIGH, TLOW and setup
hold time for both fast and fastplus. But these values can be different
for each speed mode and should be using separate variables. Split the
variables used for fast and fast plus mode.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>