counter: add new COUNTER_EVENT_CHANGE_OF_STATE

Add new counter event to notify user space about every new counter
pulse.

Link: https://lore.kernel.org/r/20220203135727.2374052-2-o.rempel@pengutronix.de
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Link: https://lore.kernel.org/r/486a5de67414470449efb84d06a2f2214f4bb31d.1647373009.git.vilhelm.gray@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>