[ARM] 3672/1: PXA: don't probe output GPIOs for interrupt

Patch from Guennadi Liakhovetski

Currently probe_irq_on() on PXA will silently reconfigure all output GPIOs, that are not configured as alternate functions, for input. Avoid that. Upon CPU reset all GPIOs are configured as inputs, so, if a GPIO is configured as output, it has been done so intentionally.

Signed-off-by: G. Liakhovetski <gl@dsa-ac.de>
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>