arm64: dts: rockchip: Set dr_mode to "host" for OTG on rk3328-roc-cc

The board has a standard USB A female port connected to the USB OTG
controller's data pins. Set dr_mode in the OTG controller node to
indicate this usage, instead of having the implementation guess.

Fixes: 2171f4fdac06 ("arm64: dts: rockchip: add roc-rk3328-cc board")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20201126073336.30794-2-wens@kernel.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3328-roc-cc.dts

@@ -334,6 +334,7 @@
 };
 
 &usb20_otg {
+	dr_mode = "host";
 	status = "okay";
 };