arm64: dts: renesas: rzg2ul-smarc-som: Enable serial NOR flash

Enable Renesas at25ql128a flash connected to QSPI0. Also disable
the node from rzfive-smarc-som as it is untested.

Tested the flash by flashing bootloaders:
flash_erase /dev/mtd0  0 0
flash_erase /dev/mtd1  0 0
mtd_debug write /dev/mtd0 0 ${BL2_FILE_SIZE} ${BL2_IMAGE}
mtd_debug write /dev/mtd1 512 ${FIP_FILE_SIZE} ${FIP_IMAGE}

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20241004173235.74307-2-biju.das.jz@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

arch/arm64/boot/dts/renesas/rzg2ul-smarc-som.dtsi

@@ -201,6 +201,12 @@ irq {
 		};
 	};
 
+	qspi0_pins: qspi0 {
+		pins = "QSPI0_IO0", "QSPI0_IO1", "QSPI0_IO2", "QSPI0_IO3",
+		       "QSPI0_SPCLK", "QSPI0_SSL";
+		power-source = <1800>;
+	};
+
 	sdhi0_emmc_pins: sd0emmc {
 		sd0_emmc_data {
 			pins = "SD0_DATA0", "SD0_DATA1", "SD0_DATA2", "SD0_DATA3",
@@ -252,6 +258,45 @@ sd0_mux_uhs {
 	};
 };
 
+&sbc {
+	pinctrl-0 = <&qspi0_pins>;
+	pinctrl-names = "default";
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <50000000>;
+		spi-tx-bus-width = <4>;
+		spi-rx-bus-width = <4>;
+
+		spi-cpol;
+		spi-cpha;
+		m25p,fast-read;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			partition@0 {
+				label = "bl2";
+				reg = <0x00000000 0x0001d000>;
+			};
+
+			partition@1d000 { /* fip is at offset 0x200 */
+				label = "fip";
+				reg = <0x0001d000 0x7e3000>;
+			};
+
+			partition@800000 {
+				label = "user";
+				reg = <0x800000 0x800000>;
+			};
+		};
+	};
+};
+
 #if (SW_SW0_DEV_SEL)
 &sdhi0 {
 	pinctrl-0 = <&sdhi0_emmc_pins>;

arch/riscv/boot/dts/renesas/rzfive-smarc-som.dtsi

@@ -6,3 +6,7 @@
  */
 
 #include <arm64/renesas/rzg2ul-smarc-som.dtsi>
+
+&sbc {
+	status = "disabled";
+};