usb: UniPhier: add UniPhier on-chip EHCI host driver support

Support EHCI host driver used on Panasonic UniPhier platform.
Since Device Tree is not supported on UniPhier yet, the base address
of USB cores are passed from board files (platdevice.c).

TODO for me:
Move the base address to device trees.

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig
index 8a6496a..30d1457 100644
--- a/drivers/usb/host/Kconfig
+++ b/drivers/usb/host/Kconfig
@@ -45,4 +45,12 @@
 
 if USB_EHCI_HCD
 
+config USB_EHCI_UNIPHIER
+	bool "Support for Panasonic UniPhier on-chip EHCI USB controller"
+	depends on ARCH_UNIPHIER
+	default y
+	---help---
+	  Enables support for the on-chip EHCI controller on Panasonic
+	  UniPhier SoCs.
+
 endif