[ARM] 5088/3: pxa2xx: add pxa2xx_set_spi_info to register pxa2xx-spi platform devices

Add a function to dynamically allocate and register pxa2xx-spi platform
devices, to be used by PXA2xx and PXA3xx based systems. Switch pcm027 and
lubbock to use it.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@pengutronix.de>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>