USB Core: hub.c: prevent re-enumeration on HNP

Patch is to prevent the OTG host of doing 3 times enumeration of
device when the Host suspends for HNP.  The error code used in
this case is ENOTSUPP.

Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>