[PATCH] USB: Support unbinding of the usb_generic driver

This patch (as556) adds support for unbinding the usb_generic "driver".
That driver only binds to USB devices, as opposed to interfaces, and it
does nothing much besides marking which struct device's go with an
overall USB device plus providing suspend/resume methods.  Now that
users can unbind drivers at will using the sysfs "unbind" attribute, we
need a rational way of dealing with USB devices that are no longer under
full control of the USB stack.  The patch handles this by unconfiguring
the device, thereby removing all the interfaces and their associated
drivers and children.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>