dt-bindings: thermal: rcar-gen3-thermal: All variants use 3 interrupts

RZ/G2M also has 3 interrupts routed to the TSC, but the list was not
updated to reflect this.

Just drop the list, as this is the case for this TSC variant in all
R-Car Gen3 and RZ/G2 SoCs.

Fixes: be6af481 ("dt-bindings: thermal: rcar-gen3-thermal: Add r8a774a1 support")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

Documentation/devicetree/bindings/thermal/rcar-gen3-thermal.txt

@@ -21,8 +21,7 @@ Required properties:
 
 Optional properties:
 
-- interrupts		: interrupts routed to the TSC (3 for H3, M3-W, M3-N,
-			  and V3H)
+- interrupts		: interrupts routed to the TSC (must be 3).
 - power-domain		: Must contain a reference to the power domain. This
 			  property is mandatory if the thermal sensor instance
 			  is part of a controllable power domain.