ARM: pxa: move pxa2xx functionality to SoC specific file
Move reset_source detection and poweroff to pxa2xx.c, to prepare the
incoming pxa3xx reset_source detection.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>