ARM: dts: r8a7794: Add Z2 clock

Add the Z2 clock (Cortex-A7 CPU core clock), which uses a fixed divider,
and link the first CPU node to it.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r8a7794.dtsi

@@ -43,6 +43,7 @@ cpu0: cpu@0 {
 			compatible = "arm,cortex-a7";
 			reg = <0>;
 			clock-frequency = <1000000000>;
+			clocks = <&z2_clk>;
 			power-domains = <&sysc R8A7794_PD_CA7_CPU0>;
 			next-level-cache = <&L2_CA7>;
 		};
@@ -1064,6 +1065,13 @@ pll1_div2_clk: pll1_div2 {
 			clock-div = <2>;
 			clock-mult = <1>;
 		};
+		z2_clk: z2 {
+			compatible = "fixed-factor-clock";
+			clocks = <&cpg_clocks R8A7794_CLK_PLL0>;
+			#clock-cells = <0>;
+			clock-div = <1>;
+			clock-mult = <1>;
+		};
 		zg_clk: zg {
 			compatible = "fixed-factor-clock";
 			clocks = <&cpg_clocks R8A7794_CLK_PLL1>;