Merge tag 'tegra-for-3.14-powergate' into drm/for-next

ARM: tegra: powergate driver changes

This branch includes all the changes to Tegra's powergate driver for 3.14.
These are separate out, since the Tegra DRM changes for 3.14 rely on the
new APIs introduced here.

A few cleanups and fixes are included, plus additions of Tegra124 SoC
support, and a new API for manipulating Tegra's IO rail deep power down
states.

This branch is based on tag tegra-for-3.14-dmas-resets-rework, in order
to avoid conflicts with the addition of common reset controller support
to the powergate driver.