ARM: dts: renesas: blanche: Add FLASH node

Add a device node for the Spansion S29GL512S NOR FLASH on the Blanche
development board.  This FLASH resides in the external address space of
the Local Bus State Controller.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/7edb26bc29ad58198901ae6b6f869684473bb29d.1693481518.git.geert+renesas@glider.be

arch/arm/boot/dts/renesas/r8a7792-blanche.dts

@@ -182,6 +182,35 @@ &can_clk {
 };
 
 &lbsc {
+	flash@0 {
+		compatible = "cfi-flash";
+		reg = <0x00000000 0x04000000>;
+		pinctrl-0 = <&flash_pins>;
+		pinctrl-names = "default";
+		bank-width = <2>;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "uboot";
+				reg = <0x00000000 0x00040000>;
+				read-only;
+			};
+			partition@40000 {
+				label = "uboot-env";
+				reg = <0x00040000 0x00040000>;
+				read-only;
+			};
+			partition@80000 {
+				label = "flash";
+				reg = <0x00080000 0x03f80000>;
+			};
+		};
+	};
+
 	ethernet@18000000 {
 		compatible = "smsc,lan89218", "smsc,lan9115";
 		reg = <0x18000000 0x100>;
@@ -240,6 +269,11 @@ du1_pins: du1 {
 		function = "du1";
 	};
 
+	flash_pins: flash {
+		groups = "lbsc_cs0";
+		function = "lbsc";
+	};
+
 	keyboard_pins: keyboard {
 		pins = "GP_3_10", "GP_3_11", "GP_3_12", "GP_3_15", "GP_11_2";
 		bias-pull-up;