Input: atmel_tsadcc - use platform parameters

Add a number of plafrom dependent parameters to atmel_tsadcc.  The
touchscreeen driver can now take into account the slight differences
that exist between IPs included in diferent products.  This will also
allow to adapt its behaivior to the caracteristics of the resistive
panel used.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>