dt-bindings: powerpc: Add Freescale/NXP MPC83xx SoCs

dt-bindings: powerpc: Add Freescale/NXP MPC83xx SoCs

Add a new binding for MPC83xx platforms, describing the board compatible
strings used in currently existing device trees.

Note that the SoC bus is called immr@... in many existing devicetrees,
but this contradicts the simple-bus binding.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: J. Neuschäfer <j.ne@posteo.net>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260303-ppcyaml-soc-v5-1-2982d5a857bc@posteo.net