clk: tegra: move CVB calculations to soc/tegra

The CVB calculations are related to DVFS and will be used by the Tegra210
DVFS code, so it makes more sense to move the functions to soc/tegra and
export them for use by the DFLL code.

Change-Id: Ib3b1b256e911baf76edddb0d90d47facaecb1d3a
Signed-off-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Reviewed-on: http://git-master/r/1258030
GVS: Gerrit_Virtual_Submit
Reviewed-by: Jon Mayo <jmayo@nvidia.com>
5 files changed