arm64: dts: ti: k3-am69-sk: Add TPS62873 node

Add DTS node for two TPS6287x high current buck convertors.

The two TPS6287x supply power to the MAIN domain for AVS and other core
supplies.

Signed-off-by: Neha Malcom Francis <n-francis@ti.com>
Link: https://lore.kernel.org/r/20240528040159.3919652-3-n-francis@ti.com


Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>