ARM: mstar: Add reboot support

MStar v7 SoCs support reset by writing a magic value to a register
in the "pmsleep" area.

This adds a node for using the syscon reboot driver to trigger a reset.
Signed-off-by: Daniel Palmer <daniel@0x0f.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/boot/dts/mstar-v7.dtsi

@@ -78,6 +78,13 @@ pmsleep: syscon@1c00 {
 				reg = <0x1c00 0x100>;
 			};
 
+			reboot {
+				compatible = "syscon-reboot";
+				regmap = <&pmsleep>;
+				offset = <0xb8>;
+				mask = <0x79>;
+			};
+
 			l3bridge: l3bridge@204400 {
 				compatible = "mstar,l3bridge";
 				reg = <0x204400 0x200>;