arm64: dts: ti: k3-j721s2: Add GPU node

The J721S2 binding is based on the TI downstream binding in 54b0f2a00d92
("arm64: dts: ti: k3-j721s2-main: add gpu node") from [1] but with updated
compatible strings.

The clock[2] and power[3] indices were verified from docs, but the
source of the interrupt index remains elusive.

References for indices: clocks[1], interrupts[2], power[3].

[1]: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel
[2]: https://downloads.ti.com/tisci/esd/latest/5_soc_doc/j721s2/clocks.html
[3]: https://downloads.ti.com/tisci/esd/latest/5_soc_doc/j721s2/devices.html



Signed-off-by: Matt Coster <matt.coster@imgtec.com>