Input: gpio_keys - more conversions to devm-* API

Replace existing gpio resource handling in the driver with managed
resources, this ensures more consistent error values and simplifies error
paths.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: remove race when instantiating polled device attributes

Polled device's attributes controlling polling rate and whether polling is
enabled are attached to input device. We should have device core
instantiate them for us, so that they are created by the time new device
notification is sent to userspace, instead of doing it ourselves
afterwards.

Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: implement managed polled input devices

Managed resources are becoming more and more popular in drivers. Let's
implement managed polled input devices, to complement managed regular input
devices.

Similarly to managed regular input devices only one new call
devm_input_allocate_polled_device() is added and the rest of APIs is
modified to work with both managed and non-managed devices.

Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: gpio_keys_polled - convert to devm-* API

Replace existing resource handling in the driver with managed device
resources, this ensures more consistent error values and simplifies error
handling paths:

kzalloc -> devm_kzalloc
gpio_request_one -> devm_gpio_request_one
input_allocate_polled_device -> devm_input_allocate_polled_device

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>