ARM: S5PV210: Add Touchscreen support for S5PV210

This patch adds touchscreen support for S5PV210.

Note: TSADC in S5PV210 support 2 touchscreen interfaces,
Only 1 is implemented as of now.

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>