[ARM] pxa: fix resume failure by saving/restoring IPRx registers

Since interrupt handler is changed to use interrupt priority, we also need
to save and restore these interrupt controller registers in suspend/resume
routine.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Tested-by: Daniel Mack <daniel@caiaq.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>