Input: samsung-keypad - favor platform data if present

We should be able to override firmware-provided parameters with in-kernel
data, if needed. To that effect favor platform data, if present, over
devicetree data.

Acked-by: Joonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>