Input: matrix_keypad - add settle time after enabling all columns

Input: matrix_keypad - add settle time after enabling all columns

Matrix keypads with high capacity need a longer settle time after
enabling all columns before re-enabling interrupts. The delay gives
the system time to settle and avoids spurious interrupts.

Add a new optional device property to configure the delay after
enabling all columns. The default is no delay.

Signed-off-by: Markus Burri <markus.burri@mt.com>
Reviewed-by: Manuel Traut <manuel.traut@mt.com>
Link: https://lore.kernel.org/r/20250110054906.354296-7-markus.burri@mt.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>