thermal: rcar_gen3_thermal: add R8A77980 support

Add the R-Car V3H (R8A77980) SoC support to the R-Car gen3 thermal driver.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>