arm64: dts: apple: t8103: Add root port interrupt routing

Add the interrupt-map properties that are required for INTx
signalling.

Tested-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Hector Martin <marcan@marcan.st>