usb: phy: add run-time dependencies to R-Car driver

The Renesas R-Car USB PHY driver only supports the R8A7778 and
R8A7779, it isn't useful on other systems unless build testing.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/Kconfig

@@ -201,6 +201,7 @@ config USB_MXS_PHY
 config USB_RCAR_PHY
 	tristate "Renesas R-Car USB PHY support"
 	depends on USB || USB_GADGET
+	depends on ARCH_R8A7778 || ARCH_R8A7779 || COMPILE_TEST
 	select USB_PHY
 	help
 	  Say Y here to add support for the Renesas R-Car USB common PHY driver.