ARM: tegra: define Tegra20 CAR binding

The Tegra20 CAR (Clock And Reset) Controller controls most aspects of
most clocks within Tegra20. The device tree binding models this as a
single monolithic clock provider, which exports many clocks. This reduces
the number of nodes needed in device tree to represent these clocks.

This binding is only useful for Tegra20; the set of clocks that exists on
Tegra30 is sufficiently different to merit its own binding.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
[pgaikwad: Added mux clk ids and sorted CAR node]
Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>