ARM: mstar: Add gpio controller to MStar base dtsi

The GPIO controller is at the same address in all of the
currently known chips so create a node for it in the base
dtsi.

Some extra properties are needed to actually use it so
disable it by default.

Signed-off-by: Daniel Palmer <[e-mail]>
Acked-by: Linus Walleij <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]'
Signed-off-by: Arnd Bergmann <[e-mail]>

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

···
 				reg = <0x204400 0x200>;
 			};
 
+			gpio: gpio@207800 {
+				#gpio-cells = <2>;
+				reg = <0x207800 0x200>;
+				gpio-controller;
+				#interrupt-cells = <2>;
+				interrupt-controller;
+				interrupt-parent = <&intc_fiq>;
+				status = "disabled";
+			};
+
 			pm_uart: uart@221000 {
 				compatible = "ns16550a";
 				reg = <0x221000 0x100>;