usb: ulpi: Add Kconfig options for ULPI

The following options can be now enabled via defconfig:
- CONFIG_USB_ULPI
- CONFIG_USB_ULPI_VIEWPORT
- CONFIG_USB_ULPI_VIEWPORT_OMAP

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 7fa99c6..bccf43e 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -53,6 +53,8 @@
 
 source "drivers/usb/emul/Kconfig"
 
+source "drivers/usb/ulpi/Kconfig"
+
 comment "USB peripherals"
 
 config USB_STORAGE