USB: don't register endpoints for interfaces that are going away

USB: don't register endpoints for interfaces that are going away

commit 352d026338378b1f13f044e33c1047da6e470056 upstream.

This patch (as1155) fixes a bug in usbcore.  When interfaces are
deleted, either because the device was disconnected or because of a
configuration change, the extra attribute files and child endpoint
devices may get left behind.  This is because the core removes them
before calling device_del().  But during device_del(), after the
driver is unbound the core will reinstall altsetting 0 and recreate
those extra attributes and children.

The patch prevents this by adding a flag to record when the interface
is in the midst of being unregistered.  When the flag is set, the
attribute files and child devices will not be created.

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