arm64: dts: rockchip: Add GPU cooling device for RK3399

As for RK3288, now that we have a binding for the GPU we can
hook up the missing cooling device for the thermal zone.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/cb905e17526d846d6d35fb86fbd3c8ba4af4cdaf.1574974673.git.robin.murphy@arm.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399.dtsi

@@ -828,6 +828,14 @@ gpu_crit: gpu_crit {
 					type = "critical";
 				};
 			};
+
+			cooling-maps {
+				map0 {
+					trip = <&gpu_alert0>;
+					cooling-device =
+						<&gpu THERMAL_NO_LIMIT THERMAL_NO_LIMIT>;
+				};
+			};
 		};
 	};
 
@@ -1887,6 +1895,7 @@ gpu: gpu@ff9a0000 {
 			     <GIC_SPI 21 IRQ_TYPE_LEVEL_HIGH 0>;
 		interrupt-names = "gpu", "job", "mmu";
 		clocks = <&cru ACLK_GPU>;
+		#cooling-cells = <2>;
 		power-domains = <&power RK3399_PD_GPU>;
 		status = "disabled";
 	};