USB: EHCI: fix remote-wakeup regression

This patch (as1097) fixes a bug in the remote-wakeup handling in
ehci-hcd.  The driver currently does not keep track of whether the
change-suspend feature is enabled for each port; the feature is
automatically reset the first time it is read.  But recent changes to
the hub driver require that the feature be read at least twice in
order to work properly.

A bit-vector is added for storing the change-suspend feature values.

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