ARM: tegra20: convert device tree files to use CLK defines

Use the Tegra20 CAR binding header (tegra20-car.h) to replace magic
numbers in the device tree. For example,

-               clocks = <&tegra_car 28>;
+               clocks = <&tegra_car CLK_HOST1X>;

Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com>
[swarren, updated since tegra20-car.h moved for consistency]
Signed-off-by: Stephen Warren <swarren@nvidia.com>