arm64: dts: tegra: smaug: Add Wi-Fi node

The Google Pixel C contains a BRCM4354 Wi-Fi + BT module.
Add a DT node for its Wi-Fi functionality. Tested on Pixel C.

Signed-off-by: Diogo Ivo <diogo.ivo@tecnico.ulisboa.pt>
Signed-off-by: Thierry Reding <treding@nvidia.com>