mesa-ci: Force db410c to host mode.

Without this, the presence of the fastboot micro cable in the CI farm
causes the HW to stay in gadget mode instead of host, so it doesn't
find the network.

arch/arm64/boot/dts/qcom/apq8016-sbc.dtsi

@@ -154,6 +154,10 @@ led@6 {
 	};
 };
 
+&usb {
+	dr_mode = "host";
+};
+
 &blsp_dma {
 	status = "okay";
 };