drivers: gpio: Fix NO_PINT_INT

Fixed #41945
NO_PINT_INT can have the same value as a specific pin.
E.G. For 1 byte pint_pin_int_t it equaled interrupt1.
Now is instead always 1 higher than the highest pin.
Expects fsl to keep setting values from 0 to
(number of connected outputs - 1)

Signed-off-by: Martin Koehler <koehler@metratec.com>