TI's J721E SoC has a 9 port Ethernet Switch instance with 8 external
ports and 1 host port, referred to as CPSW9G.

Add device-tree nodes for CPSW9G and disable it by default. Device-tree
overlays will be used to enable it.
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/20230315062307.1612220-2-s-vadapalli@ti.comSigned-off-by: Nishanth Menon <nm@ti.com>