fix(el3-runtime): leverage generic interrupt controller helpers

Rather than validating the type of interrupts supported by the
platform interrupt controller, the interrupt management framework can
directly use helper utilities implemented by the generic interrupt
controller driver.

Change-Id: I735f8d2742a2c7974d11c0a5ddc771ad807c635c
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
3 files changed