Input: clps711x-keypad - switch to using polled mode of input devices

Input: clps711x-keypad - 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 clps711x-keypad driver to use the
polling mode of standard input devices and removes dependency on
INPUT_POLLDEV.

Also use managed API when allocating input device, this allows us to remove
clps711x_keypad_remove() method.

Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Marco Felsch <m.felsch@pengutronix.de>
Link: https://lore.kernel.org/r/20191017204217.106453-7-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>