PM / devfreq: tegra: Reconfigure hardware on governor's restart

Move hardware configuration to governor's start/resume methods.
This allows to re-initialize hardware counters and reconfigure
cleanly if governor was stopped/paused. That is needed because we
are not aware of all hardware changes that happened while governor
was stopped and the paused state may get out of sync with reality,
hence it's better to start with a clean slate after the pause. In
a result there is no memory bandwidth starvation after resume from
suspend-to-ram that results in display controller underflowing that
happens on resume because of improper decision made by devfreq about
the required memory frequency. This change also cleans up code a tad
by moving hardware-configuration code into a single location.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>