arm64: dts: ti: k3-j721s2-main: Add DSS node

Add DSS node for J721S2 SoC. DSS IP in J721S2 is
same as DSS IP in J721E, so same compatible is used.

Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://lore.kernel.org/r/20230803081800.368582-2-j-choudhary@ti.com


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