drivers: gpio: nrfx: Use mask to determine if sense is used

So far driver was using SENSE mechanism for all or none edge
interrupts. This was not convenient since in some modules may
require IN event to be used and other did not. Converting it to
use a mask specified in the device tree. Pins indicated in the
mask will use sensing.

Signed-off-by: Krzysztof Chruscinski <krzysztof.chruscinski@nordicsemi.no>