arm64: dts: stingray: Add Stingray Thermal DT support.

Add DT nodes for thermal zones memory base address
to read temperature.

Signed-off-by: Pramod Kumar <pramod.kumar@broadcom.com>
Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>