Input: ads7846 - make sure we do not change platform data
Input: ads7846 - make sure we do not change platform data

Let's declare platform data a const pointer so that we don't accitentally
change it. Also fetch it with dev_get_platdata().

Signed-off-by: Dmitry Torokhov <6b8646d310837fed93a129ed3c979b90c7f2674f@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs