ARM: pxa: pxa27x: Don't map IMEMC region statically

The IMEMC mapping not only has no user, but maps a reserved memory
space. It just wastes vmalloc space, remove it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Olof Johansson <olof@lixom.net>