dt-bindings: thermal: rcar-gen3-thermal: use positive logic

dt-bindings: thermal: rcar-gen3-thermal: use positive logic

When handling the V3U/r8a779a0 exception, avoid using 'not:' because
then its subschemas are far away in the 'else:' branch. Keep them
together using positive logic.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20220610201701.7946-1-wsa+renesas@sang-engineering.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>