[ARM] 2897/2: PXA2xx IRDA support

Patch from Nicolas Pitre

This is the PXA2xx common IRDA driver, plus platform support
for Lubbock and Mainstone.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Acked-by: Jean Tourrilhes <jt@hpl.hp.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>