Input: add S3C24XX touchscreen driver

S3C24XX touchscreen driver, originally written by Arnaud Patard and
other contributors. The driver has had substantial testing as well as
a number of tidying up passes done by Ben Dooks, as noted:

- added kernel-doc comments to most of the routines
- removed old code from pre adc framework days
- updated device probe code to use platform id list matching
- cleaned up debug, since printk() now has timestamp feature
- ensure code uses dev_() reporting macros where necessary
- remove ABS_PRESSURE reporting, tslib can be fixed
- ensure timer is removed on driver exit
- move to using dev_pmops for power management

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>