usb: chipidea: fix the build error with randconfig

Using below  configs, the compile will have error:
ERROR: "ehci_init_driver" undefined!

.config:
CONFIG_USB_CHIPIDEA=m
CONFIG_USB_CHIPIDEA_HOST=y
CONFIG_USB_CHIPIDEA_DEBUG=y

The reason is chipidea host uses symbol from ehci, but ehci
is not compiled. Let the chipidea host depend on
ehci even it is built as module.

Signed-off-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

@@ -12,7 +12,7 @@ if USB_CHIPIDEA
 
 config USB_CHIPIDEA_UDC
 	bool "ChipIdea device controller"
-	depends on USB_GADGET=y || USB_CHIPIDEA=m
+	depends on USB_GADGET=y || (USB_CHIPIDEA=m && USB_GADGET=m)
 	help
 	  Say Y here to enable device controller functionality of the
 	  ChipIdea driver.
@@ -20,7 +20,7 @@ config USB_CHIPIDEA_UDC
 config USB_CHIPIDEA_HOST
 	bool "ChipIdea host controller"
 	depends on USB=y
-	depends on USB_EHCI_HCD=y || USB_CHIPIDEA=m
+	depends on USB_EHCI_HCD=y || (USB_CHIPIDEA=m && USB_EHCI_HCD=m)
 	select USB_EHCI_ROOT_HUB_TT
 	help
 	  Say Y here to enable host controller functionality of the