arm64: dts: ti: k3-am64-main: add VTM node

The am64x supports a single VTM module which is located in the main
domain with two associated temperature monitors located at different hot
spots on the die.

Tested-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: Bryan Brattlof <bb@ti.com>
Link: https://lore.kernel.org/r/20230405215328.3755561-2-bb@ti.com


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