arm64: tegra: smaug: Declare cros-ec extcon

Leverage the Chrome OS EC in the Pixel C to convey information about the
state of the USB-C port via the extcon class.

Signed-off-by: Diogo Ivo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Thierry Reding <[e-mail]>

arch/arm64/boot/dts/nvidia/tegra210-smaug.dts

···
 					reg = <0x55>;
 				};
 			};
+
+			usbc_extcon0: extcon0 {
+				compatible = "google,extcon-usbc-cros-ec";
+				google,usb-port-id = <0>;
+			};
 		};
 	};