EHCI: centralize controller suspend/resume

This patch (as1563) removes a lot of duplicated code by moving the
EHCI controller suspend/resume routines into the core driver, where
the various platform drivers can invoke them as needed.

Not only does this simplify these platform drivers, this also makes it
easier for other platform drivers to add suspend/resume support in the
future.

Note: The patch does not touch the ehci-fsl.c file, because its
approach to suspend and resume is so different from all the others.
It will have to be handled specially by its maintainer.

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