arm64: dts: ti: k3-j721s2-main: Add main CPSW2G devicetree node

TI's J721S2 SoC has a MAIN CPSW2G instance of the CPSW Ethernet Switch.
Add devicetree node for it.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Link: https://lore.kernel.org/r/20230726065407.378455-2-s-vadapalli@ti.com


Signed-off-by: Nishanth Menon <nm@ti.com>