Input: matrix_keypad - remove support for clustered interrupt

There are no users of this functionality in the mainline kernel (it was
only available to boards using platform data and not device tree).
Remove it to simplify the code.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240805014710.1961677-2-dmitry.torokhov@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>