usb: host: Add simple of glue driver for DWC3 USB Controllers integration

This is a port of the dwc3-of-simple driver from Linux to enable/deassert
clock and resets of a simple DWC3 Controller HW glue.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index 9819489..abe4f90 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -49,6 +49,7 @@
 # xhci
 obj-$(CONFIG_USB_XHCI_HCD) += xhci.o xhci-mem.o xhci-ring.o
 obj-$(CONFIG_USB_XHCI_DWC3) += xhci-dwc3.o
+obj-$(CONFIG_USB_XHCI_DWC3_OF_SIMPLE) += dwc3-of-simple.o
 obj-$(CONFIG_USB_XHCI_ROCKCHIP) += xhci-rockchip.o
 obj-$(CONFIG_USB_XHCI_ZYNQMP) += xhci-zynqmp.o
 obj-$(CONFIG_USB_XHCI_KEYSTONE) += xhci-keystone.o