[PATCH] USB: otg hub support is optional

USB OTG devices are not required to support external hubs.  This adds a
configuration option to disable that support.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index ff03184..a08787e 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -99,4 +99,11 @@
 	  normal Linux-USB hosts do (other than the warning), and is
 	  convenient for many stages of product development.
 
+config USB_OTG_BLACKLIST_HUB
+	bool "Disable external hubs"
+	depends on USB_OTG
+	help
+	  If you say Y here, then Linux will refuse to enumerate
+	  external hubs.  OTG hosts are allowed to reduce hardware
+	  and software costs by not supporting external hubs.