powerpc/86xx: Add power management support for MPC8610HPCD boards

This patch adds needed nodes and properties to support suspend/resume
on the MPC8610HPCD boards.

There is a dedicated switch (SW9) that is used to wake up the boards.
By default the SW9 button is routed to IRQ8, but could be re-routed
(via PIXIS) to sreset.

With 'no_console_suspend' kernel command line argument specified, the
board is also able to wakeup upon serial port input.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Acked-by: Scott Wood <scottwood@freescale.com> [dts]
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>