arm64: dts: ti: k3-am65: Relocate thermal-zones to SoC specific location

When commit 64f9147d ("arm64: dts: ti: am654: Add thermal
zones") introduced thermal-zones for am654, it defined as under the
common am65-wakeup bus segment, when it is am654 specific (other SoC
spins can have slightly different thermal characteristics). Futher,
thermal-zones is introduced under simple-bus node, when it has no
actual register or base address.

So, move it to it's rightful place under am654 SoC dtsi under the base
node.

Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Keerthy <j-keerthy@ti.com>
Link: https://lore.kernel.org/r/20210916181801.32588-1-nm@ti.com