arm64: dts: apple: Add J375 devicetrees

These are the Mac Studio devices with M1 Max (t6001) and
M1 Ultra (t6002).

Signed-off-by: Janne Grunau <j@jannau.net>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Hector Martin <marcan@marcan.st>