arm64: dts: apple: Add J180d (Mac Pro, M2 Ultra, 2023) device tree

arm64: dts: apple: Add J180d (Mac Pro, M2 Ultra, 2023) device tree

The M2 Ultra in the Mac Pro differs from the M2 Ultra Mac Studio in its
PCIe setup. It uses all available 16 PCIe Gen4 on the first die and 8
PCIe Gen4 lanes on the second die to connect to a 100 lane Microchip
Switchtec PCIe switch. All internal PCIe devices and the PCIe slots are
connected to the PCIe switch.
Each die implements a PCIe controller with a single 16 or 8 lane port.
The PCIe controller is mostly compatible with existing implementation
in pcie-apple.c.
The resources for other 8 lanes on the second die are used to connect
the NVMe flash with the controller in the SoC.
This initial device tree does not include PCIe support.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Co-developed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Sven Peter <sven@kernel.org>
Signed-off-by: Sven Peter <sven@kernel.org>