ARM: tegra: implement common DMA and resets DT bindings

This series converts the Tegra DTs and drivers to use the common/
standard DMA and reset bindings, rather than custom bindings. It also
adds complete documentation for the Tegra clock bindings without
actually changing any binding definitions.

This conversion relies on a few sets of patches in branches from outside
the Tegra tree:

1) A patch to add an DMA channel request API which allows deferred probe
   to be implemented.

2) A patch to implement a common part of the of_xlate function for DMA
   controllers.

3) Some ASoC patches (which in turn rely on (1) above), which support
   deferred probe during DMA channel allocation.

4) The Tegra clock driver changes for 3.14.

Consequently, this branch is based on a merge of all of those external
branches.

In turn, this branch is or will be pulled into a few places that either
rely on features introduced here, or would otherwise conflict with the
patches:

a) Tegra's own for-3.14/powergate and for-4.14/dt branches, to avoid
   conflicts.

b) The DRM tree, which introduces new code that relies on the reset
   controller framework introduced in this branch, and to avoid
   conflicts.