ARM: dts: sun8i: Add R_CPUCFG device node for the A83T dtsi

The R_CPUCFG is a collection of registers needed for SMP bringup
on clusters and cluster's reset.
For the moment, documentation about this register is found in
Allwinner's code only.
Signed-off-by: Mylène Josserand <mylene.josserand@bootlin.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm/boot/dts/sun8i-a83t.dtsi

@@ -938,6 +938,11 @@ r_ccu: clock@1f01400 {
 			#reset-cells = <1>;
 		};
 
+		r_cpucfg@1f01c00 {
+			compatible = "allwinner,sun8i-a83t-r-cpucfg";
+			reg = <0x1f01c00 0x400>;
+		};
+
 		r_pio: pinctrl@1f02c00 {
 			compatible = "allwinner,sun8i-a83t-r-pinctrl";
 			reg = <0x01f02c00 0x400>;