usb: chipidea: fix and improve dependencies if usb host or gadget support is built as module

Since commit "5e0aa49e usb: chipidea: use generic map/unmap routines",
the udc part of the chipidea driver needs the generic usb gadget helper
functions. If the chipidea driver with udc support is built into the
kernel and usb gadget is built a module, the linking of the kernel
fails with:

drivers/built-in.o: In function `_hardware_dequeue':
drivers/usb/chipidea/udc.c:527:
    undefined reference to `usb_gadget_unmap_request'
drivers/usb/chipidea/udc.c:1269:
    undefined reference to `usb_gadget_unmap_request'
drivers/usb/chipidea/udc.c:1821:
    undefined reference to `usb_del_gadget_udc'
drivers/usb/chipidea/udc.c:443:
    undefined reference to `usb_gadget_map_request'
drivers/usb/chipidea/udc.c:1774:
    undefined reference to `usb_add_gadget_udc'

This patch changes the dependencies, so that udc support can only be
activated if the linux gadget support (USB_GADGET) is builtin or both
chipidea driver and USB_GADGET are modular. Same dependencies for the
chipidea host support and the linux host side USB support (USB).

While there, fix the indention of chipidea the help text.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/Kconfig

 config USB_CHIPIDEA
 	tristate "ChipIdea Highspeed Dual Role Controller"
-	depends on USB
+	depends on USB || 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
@@ -12,7 +12,7 @@ if USB_CHIPIDEA
 
 config USB_CHIPIDEA_UDC
 	bool "ChipIdea device controller"
-	depends on USB_GADGET
+	depends on USB_GADGET=y || USB_GADGET=USB_CHIPIDEA
 	select USB_GADGET_DUALSPEED
 	help
 	  Say Y here to enable device controller functionality of the
@@ -20,6 +20,7 @@ config USB_CHIPIDEA_UDC
 
 config USB_CHIPIDEA_HOST
 	bool "ChipIdea host controller"
+	depends on USB=y || USB=USB_CHIPIDEA
 	select USB_EHCI_ROOT_HUB_TT
 	help
 	  Say Y here to enable host controller functionality of the