Input: psxpad-spi - switch to using polled mode of input devices

We have added polled mode to the normal input devices with the intent of
retiring input_polled_dev. This converts psxpad-spi driver to use the
polling mode of standard input devices and removes dependency on
INPUT_POLLDEV.

Link: https://lore.kernel.org/r/20191001220421.GA66693@dtor-ws


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>