Yes, what you’re seeing that’s expected. At the moment, there is no device-tree source for the Raspberry Pi 5 in the upstream Linux kernel (as of linux-next-20231117).
There needs to be a file called bcm2712.dtsi (for the BCM2712 SoC) and a file called bcm2712-rpi-5-b.dts (for the Raspberry Pi 5 itself) here (for arm32) and here (for arm64).
It will be enabled once the code lands in upstream (kernel.org). I believe once that’s ready, we should have a public announcement since the Raspberry Pi lineup is a big deal in the SBC space.