irqchip/uniphier-aidet: Add compatible string for NX1 SoC

Add the compatible string to support UniPhier NX1 SoC, which has the same
kinds of controls as the other UniPhier SoCs.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/1653023822-19229-3-git-send-email-hayashi.kunihiko@socionext.com