rockchip: select DM_USB for rockchip SoC

Select DM_USB to compatible with USB DM driver model.

Signed-off-by: MengDongyang <daniel.meng@rock-chips.com>
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Acked-by: Simon Glass <sjg@chromium.org>

arch/arm/Kconfig

@@ -896,6 +896,7 @@ config ARCH_ROCKCHIP
 	select DM_SERIAL
 	select DM_SPI
 	select DM_SPI_FLASH
+	select DM_USB if USB
 
 config TARGET_THUNDERX_88XX
 	bool "Support ThunderX 88xx"