arm64: dts: r8a7795: Add CAN external clock support

Adds external CAN clock node for r8a7795. This clock can be used as
fCAN clock of CAN and CAN FD controller.

Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a7795.dtsi

@@ -115,6 +115,14 @@
 		clock-frequency = <0>;
 	};
 
+	/* External CAN clock - to be overridden by boards that provide it */
+	can_clk: can {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <0>;
+		status = "disabled";
+	};
+
 	/* External SCIF clock - to be overridden by boards that provide it */
 	scif_clk: scif {
 		compatible = "fixed-clock";