dt-bindings: touchscreen: add debounce-delay-us property

dt-bindings: touchscreen: add debounce-delay-us property

Add support for glitch delay configuration. A detected signal is valid
only if it remains stable longer than the configured delay; otherwise,
it is considered a glitch.

This property was introduced for the i.MX6UL touchscreen controller (TSC),
which provides a hardware deglitch filter with four thresholds depending
on the IPG clock frequency. In this use case, the IPG clock rate is 66 MHz,
resulting in thresholds of 124 µs, 62 µs, 31 µs, and 15 µs, which requires
a property with microsecond-level resolution.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250923143746.2857292-4-dario.binacchi@amarulasolutions.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>