PM / devfreq: tegra: Clean up driver's probe / remove

Reset hardware, disable ACTMON clock, release OPP's and handle all
possible error cases correctly, maintaining the correct tear down
order. Also use devm_platform_ioremap_resource() which is now available
in the kernel.

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>