gpio: gpio-adp5588: drop the driver

gpio: gpio-adp5588: drop the driver

With commit bcfed9ff6756 ("Input: adp5588-keys - support gpi key events as
'gpio keys'") the irchip functionality is directly supported in the input
driver as the main goal of these pins is to be used as gpio keys. Hence,
this driver can be removed.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Acked-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220829131553.690063-3-nuno.sa@analog.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>