dm: usb: exynos: Use driver model for USB

Convert Exynos boards over to use driver model for USB. This does not remove
any unnecessary code so far.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NMarek Vasut <marex@denx.de>

arch/arm/cpu/armv7/exynos/Kconfig

@@ -80,6 +80,9 @@ config DM_SPI_FLASH
 config DM_GPIO
 	default y
 
+config DM_USB
+	default y
+
 source "board/samsung/smdkv310/Kconfig"
 source "board/samsung/trats/Kconfig"
 source "board/samsung/universal_c210/Kconfig"