ARM: tegra: update *.dts for regulator-compatible deprecation

Commit 13511de "regulator: deprecate regulator-compatible DT property"
now allows for simpler content within the regulators node within a PMIC.
Modify all the Tegra device tree files to take advantage of this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>