ARM: shmobile: genmai dts: Replace status value "ok" by "okay"

While the DT parsing code recognizes "ok" as a valid value for the
"status" property, ePAPR v1.1 doesn't mention it in the list of valid
values.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r7s72100-genmai.dts

@@ -45,7 +45,7 @@ &usb_x1_clk {
 };
 
 &mtu2 {
-	status = "ok";
+	status = "okay";
 };
 
 &i2c2 {