usb: xhci: Add Renesas R-Car xHCI driver

Add firmware V3, firmware loader and XHCI glue for the Renesas R-Car
Gen3 SoCs XHCI controller. Thus far only the R-Car Gen3 R8A7795 ES2.0+
and R8A7796 are supported.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 5264475..c79f866 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -47,6 +47,14 @@
 	help
 	  Enables support for the on-chip xHCI controller on Rockchip SoCs.
 
+config USB_XHCI_RCAR
+	bool "Renesas RCar USB 3.0 support"
+	default y
+	depends on ARCH_RMOBILE
+	help
+	  Choose this option to add support for USB 3.0 driver on Renesas
+	  RCar Gen3 SoCs.
+
 config USB_XHCI_STI
 	bool "Support for STMicroelectronics STiH407 family on-chip xHCI USB controller"
 	depends on ARCH_STI