extcon: arizona: Suppress duplicate JACKDET reports

In cases where we see a brief (dis)connection of the jack detection signals
we may see a noop jack insertion or removal where the jack has returned to
the original state by the time the interrupt is serviced. Suppress these
events in order to save work and avoid confusing the rest of the code.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>