intc: add NXP S32 WKPU interrupt controller driver

Introduce an interrupt controller for the NXP S32 WKPU peripheral
that can be integrated with GPIO to trigger interrupts through
external interrupt pad inputs.

WKPU can trigger interrupts from certain input pads that support this
function, as well as wake-up events to the power management domain. This
patch only adds WKPU functionality as an interrupt controller to extend
the number of input pads that can interrupt the core. Power management
functionalities are not supported.

Signed-off-by: Manuel Argüelles <manuel.arguelles@nxp.com>