usb: chipidea: improve kconfig 2.0

This patch provides a cleaner solution to the problem described in
commit 20a677fd ("usb: chipidea: improve kconfig").

The goal to be achieved is to force USB_CHIPIDEA=m if either
USB_EHCI_HCD=m or USB_GADGET=m.
If both are 'y' USB_CHIPIDEA may be selected to be 'm' or 'y'.

The old patch had the drawback, that USB_CHIPIDEA could be chosen as
'y' though USB_EHCI_HCD or USB_GADGET (or both) were 'm' leading to a
situation where USB_CHIPIDEA_HOST or USB_CHIPIDEA_UDC vanished from
the config options producing a compilable but dysfunctional driver.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Reviewed-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/Kconfig

@@ -1,6 +1,6 @@
 config USB_CHIPIDEA
 	tristate "ChipIdea Highspeed Dual Role Controller"
-	depends on USB || USB_GADGET
+	depends on (USB_EHCI_HCD && USB_GADGET) || (USB_EHCI_HCD && !USB_GADGET) || (!USB_EHCI_HCD && USB_GADGET)
 	help
 	  Say Y here if your system has a dual role high speed USB
 	  controller based on ChipIdea silicon IP. Currently, only the
@@ -12,15 +12,14 @@ if USB_CHIPIDEA
 
 config USB_CHIPIDEA_UDC
 	bool "ChipIdea device controller"
-	depends on USB_GADGET=y || (USB_CHIPIDEA=m && USB_GADGET=m)
+	depends on USB_GADGET
 	help
 	  Say Y here to enable device controller functionality of the
 	  ChipIdea driver.
 
 config USB_CHIPIDEA_HOST
 	bool "ChipIdea host controller"
-	depends on USB=y
-	depends on USB_EHCI_HCD=y || (USB_CHIPIDEA=m && USB_EHCI_HCD=m)
+	depends on USB_EHCI_HCD
 	select USB_EHCI_ROOT_HUB_TT
 	help
 	  Say Y here to enable host controller functionality of the