ARM: S3C64XX: Add Touchscreen support for S3C64XX

This patch adds touchscreen support for S3C64XX.

Signed-off-by: Naveen Krishna Ch <ch.naveen@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
[ben-linux@fluff.org: minor title fix]
Signed-off-by: Ben Dooks <ben-linux@fluff.org>