ARM: tegra: correct Colibri T20 regulator settings

Set the parent of the regulators LDO2 to LDO9 according to the
schematic. Set the base voltage to 3.3V, there is only 3.3V on the
module itself.

Set the Core and CPU voltage to the specified voltages of 1.2V and
1.0V respectivly.

LDO6 should deliver 2.85V. The attached peripherals were not in
use so far.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Stephen Warren <swarren@nvidia.com>