gpio: gpio-adp5588: drop the driver

With commit 9d2b2e83 ("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>