Add support for PoV Protab2 XXL

Very similar to protab2 but with half the ram. No compatible 432 MHz
found previously.

For more info http://linux-sunxi.org/Point_Of_View_ProTab2_XXL

Thanks to Aexl Fowley <aexlfowley@web.de>

Signed-off-by: Oliver Schinagl <oliver@schinagl.nl>