Input: silead - use devm_gpiod_get

The silead code is using devm_foo for everything (and does not free
any resources). Except that it is using gpiod_get instead of
devm_gpiod_get (but is not freeing the gpio_desc), change this
to use devm_gpiod_get so that the gpio will be properly released.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>