Trusted Execution: API for configuring HW interrupts to target desired security domain

[ioannisg]

In a trusted execution framework, interrupts from external sources may need to have different security attributions. We need an API to allocate the existing interrupt signals to target either the Secure or the non-Secure domain.

Note: this is part of the required API for Trusted Execution (any arch supporting Trusted Execution must implement this functionality)