USB: OHCI: make ohci-da8xx a separate driver

Separate the Davinci OHCI host controller driver from ohci-hcd
host code so that it can be built as a separate driver module.
This work is part of enabling multi-platform kernels on ARM

Tested-by: David Lechner <david@lechnology.com>
Signed-off-by: Manjunath Goudar <manjunath.goudar@linaro.org>
[Axel: adapted and rebased, fixed minor comments]
Signed-off-by: Axel Haslam <ahaslam@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/Kconfig

@@ -479,9 +479,9 @@ config USB_OHCI_HCD_OMAP3
 	  OMAP3 and later chips.
 
 config USB_OHCI_HCD_DAVINCI
-	bool "OHCI support for TI DaVinci DA8xx"
+	tristate "OHCI support for TI DaVinci DA8xx"
 	depends on ARCH_DAVINCI_DA8XX
-	depends on USB_OHCI_HCD=y
+	depends on USB_OHCI_HCD
 	select PHY_DA8XX_USB
 	default y
 	help