dt-bindings: thermal: rcar-gen3-thermal: Add r8a779a0 support

Add support for R-Car V3U. The V3U IP differs a bit from its siblings in
such way that it have 4 TSC nodes and the interrupts are not routed to
the INTC-AP but to the ECM.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20201126223028.3119044-2-niklas.soderlund+renesas@ragnatech.se