Input: st1232 - remove obsolete platform device support

Commit 1fa59bda

 ("ARM: shmobile: Remove legacy board code for
Armadillo-800 EVA"), removed the last user of st1232_pdata and the
"st1232-ts" platform device.  All remaining users use DT.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>