devicetree: Adjust status "ok" -> "okay" under drivers/of/

Tweak a small number of status "ok" lines in a single file under
/drivers/of/ to use the proper DTSpec 0.1 spelling of "okay".
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Rob Herring <robh@kernel.org>

drivers/of/unittest-data/overlay.dts

@@ -7,7 +7,7 @@ fragment@0 {
 		target = <&electric_1>;
 
 		__overlay__ {
-			status = "ok";
+			status = "okay";
 
 			hvac_2: hvac-large-1 {
 				compatible = "ot,hvac-large";
@@ -23,7 +23,7 @@ fragment@1 {
 		__overlay__ {
 			#address-cells = <1>;
 			#size-cells = <1>;
-			status = "ok";
+			status = "okay";
 
 			ride@100 {
 				#address-cells = <1>;
@@ -67,7 +67,7 @@ fragment@2 {
 		target = <&lights_2>;
 
 		__overlay__ {
-			status = "ok";
+			status = "okay";
 			color = "purple", "white", "red", "green";
 			rate = < 3 256 >;
 		};