dt-bindings: apple,aic: Add CPU PMU per-cpu pseudo-interrupts

Advertise the two pseudo-interrupts that tied to the two PMU
flavours present in the Apple M1 SoC.

We choose the expose two different pseudo-interrupts to the OS
as the e-core PMU is obviously different from the p-core one,
effectively presenting two different devices.

Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Marc Zyngier <maz@kernel.org>