[ARM] 3231/1: mx1ads board support cleanup

Patch from Sascha Hauer

- remove unnecessary mappings
- rename mx1ads_device to cs89x0_device, because
  that's what it is
- fix io/irq resource for cs89x0 device

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>