Patch from Todd Poynor

Add support for PXA27x Standby mode, a low-power mode that retains CPU
and some peripheral state (the existing "sleep" mode is a power-power
mode that retains less state). Activated via:
echo -n standby > /sys/power/state
From: David Burrage and Todd Poynor
Signed-off-by: NTodd Poynor <tpoynor@mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>