ARM: dt: dove: add GPU power domain description

Add the description of the GPU power domain to the PMU DT entry.

Signed-off-by: Russell King <[e-mail]>
Signed-off-by: Andrew Lunn <[e-mail]>
Signed-off-by: Gregory CLEMENT <[e-mail]>

arch/arm/boot/dts/dove.dtsi

···
 						marvell,pmu_iso_mask = <0x00000001>;
 						resets = <&pmu 16>;
 					};
+
+					gpu_domain: gpu-domain {
+						#power-domain-cells = <0>;
+						marvell,pmu_pwr_mask = <0x00000004>;
+						marvell,pmu_iso_mask = <0x00000002>;
+						resets = <&pmu 18>;
+					};
 				};
 
 				thermal: thermal-diode@001c {