ARM: S5P6440: Add new Kconfig and Makefiles

This patch adds the Kconfig and Makefile for the new S5P6440 machine
and platform directories. It also updates arch/arm Kconfig and Makefiles
to include the support for the new S5P6440 CPU.

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>