irqchip/al-fic: Introduce Amazon's Annapurna Labs Fabric Interrupt Controller Driver

The Amazon's Annapurna Labs Fabric Interrupt Controller has 32 inputs.
A FIC (Fabric Interrupt Controller) may be cascaded into another FIC or
directly to the main CPU Interrupt Controller (e.g. GIC).

Signed-off-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>