ARM: tegra: dvfs: Predict required voltage for a given freq

ARM: tegra: dvfs: Predict required voltage for a given freq

Export the tegra_dvfs_predict_millivolts interface to drivers to be
used during tuning and getting the minimum core voltage for a given
frequency.

Bug 1423429

Reviewed-on: http://git-master/r/359374
(cherry picked from commit 363ba00eab262307efc02880db06b1c5fb67fa92)

Change-Id: I9dbadd831fa2f5b940ffb305a25ab56de63eec6e
Signed-off-by: Naveen Kumar Arepalli <naveenk@nvidia.com>
Signed-off-by: R Raj Kumar <rrajk@nvidia.com>
Reviewed-on: http://git-master/r/363809
Reviewed-by: Bitan Biswas <bbiswas@nvidia.com>