counter: add direction change event

Add COUNTER_EVENT_DIRECTION_CHANGE to be used by drivers to emit events
when a counter detects a change in direction.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20250110-counter-ti-eqep-add-direction-support-v2-2-c6b6f96d2db9@baylibre.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Author: dlech

include/uapi/linux/counter.h

@@ -65,6 +65,8 @@ enum counter_event_type {
 	COUNTER_EVENT_CHANGE_OF_STATE,
 	/* Count value captured */
 	COUNTER_EVENT_CAPTURE,
+	/* Direction change detected */
+	COUNTER_EVENT_DIRECTION_CHANGE,
 };
 
 /**