[MTD] MAPS: Merge Lubbock and Mainstone drivers into common PXA2xx driver

Replace Lubbock and Mainstone board drivers with common PXA2xx driver,
convert to platform driver (corresponding platform device changes merged
to kernel.org for 2.6.15), add power management callbacks.

Signed-off-by: Todd Poynor <tpoynor@mvista.com>
Signed-off-by: Nicolas Pitre <npitre@mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>