usb: xhci: octeon: Add DWC3 glue layer for Octeon

This patch adds the glue layer for the MIPS Octeon SoCs. It's ported
mainly from the Linux code.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 4eb7b34..0971a7c 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -46,6 +46,15 @@
 	  SoCs, which includes Armada8K, Armada3700 and other Armada
 	  family SoCs.
 
+config USB_XHCI_OCTEON
+	bool "Support for Marvell Octeon family on-chip xHCI USB controller"
+	depends on ARCH_OCTEON
+	default y
+	help
+	  Enables support for the on-chip xHCI controller on Marvell Octeon
+	  family SoCs. This is a driver for the dwc3 to provide the glue logic
+	  to configure the controller.
+
 config USB_XHCI_PCI
 	bool "Support for PCI-based xHCI USB controller"
 	depends on DM_USB