ARM: dts: renesas: r8a7778: Add missing unit address to bus node

Add missing unit address to bus node to fix the following DTC W=1
warning:

    arch/arm/boot/dts/renesas/r8a7778.dtsi:43.12-48.4: Warning (unit_address_vs_reg): /bus: node has a reg or ranges property, but no unit name

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/20260327234244.91707-2-marek.vasut+renesas@mailbox.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Author: Marek Vasut

arch/arm/boot/dts/renesas/r8a7778.dtsi

@@ -40,7 +40,7 @@
 		spi2 = &hspi2;
 	};
 
-	lbsc: bus {
+	lbsc: bus@0 {
 		compatible = "simple-bus";
 		#address-cells = <1>;
 		#size-cells = <1>;