arm64: dts: apm: Remove unused and undocumented "bus_num" property

Remove "bus_num" property which is both unused in the kernel and
undocumented. Most likely they are leftovers from downstream.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20241115195049.3637454-2-robh@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>