arm64: tegra: Add ethernet controller on Tegra194

The Tegra194 contains the same ethernet controller as the Tegra186.
Add the device tree node for it, and correspondingly the PHY node
on the board device tree.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>