hwmon: tegra: tsensor: improve counter accuracy

hwmon: tegra: tsensor: improve counter accuracy

When set threshold of tsensor,convert the temp to counter.
The counter convert from temp is with ~1.8C average error.
Improved the accuracy, make it to be ~0.1C.

Bug 1015288

Change-Id: Icab03b559eaeb8846dd1191869afe39c9965f934
Signed-off-by: Daniel Fu <danifu@nvidia.com>
Reviewed-on: http://git-master/r/114904
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>
Rebase-Id: Rbac6bde6ff6d5681135fe41fe0c20c27d9a8020a