Input: s3c24xx_ts - Add FEAT for Samsung touchscreen support

This patch adds a feature bit field in the touchscreen driver for Samsung SoCs.
Which can be used to distinguish the TSADC module features.

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