ARM: dts: nspire: Use syscon-reboot to handle restart

Writing this bit can be handled by the syscon-reboot driver.
Add this node to DT.
Signed-off-by: Andrew Davis <afd@ti.com>
Tested-by: Fabian Vogt <fabian@ritter-vogt.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Fabian Vogt <fabian@ritter-vogt.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/nspire/nspire.dtsi

@@ -172,7 +172,14 @@ rtc: rtc@90090000 {
 			};
 
 			misc: misc@900a0000 {
+				compatible = "ti,nspire-misc", "syscon", "simple-mfd";
 				reg = <0x900a0000 0x1000>;
+
+				reboot {
+					compatible = "syscon-reboot";
+					offset = <0x08>;
+					value = <0x02>;
+				};
 			};
 
 			pwr: pwr@900b0000 {