input: tps65218-pwrbutton: Add platform_device_id table

platform_device_id table is needed for adding the tps65218-pwrbutton
module to the mfd_cell array.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>