ARM: dts: microchip: sama7g54_curiosity: Add fixed-partitions for spi-nor flash

Add fixed-partitions for spi-nor flash to match the at91 boot flow
and layout of the nand flash.
Partitions can be listed from /proc/mtd:

[root@sama7g54 ~]$ cat /proc/mtd | grep qspi
mtd6: 00040000 00001000 "qspi1: at91bootstrap"
mtd7: 00100000 00001000 "qspi1: u-boot"
mtd8: 00040000 00001000 "qspi1: u-boot env"
mtd9: 00080000 00001000 "qspi1: device tree"
mtd10: 00600000 00001000 "qspi1: kernel"

[root@sama7g54 ~]$ mtdinfo /dev/mtd10
mtd10
Name:                           qspi1: kernel
Type:                           nor
Eraseblock size:                4096 bytes, 4.0 KiB
Amount of eraseblocks:          1536 (6291456 bytes, 6.0 MiB)
Minimum input/output unit size: 1 byte
Sub-page size:                  1 byte
Character device major/minor:   90:20
Bad blocks are allowed:         false
Device is writable:             true

Signed-off-by: Mihai Sain <mihai.sain@microchip.com>
Link: https://lore.kernel.org/r/20250429064547.5807-1-mihai.sain@microchip.com
Signed-off-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>

Author: Mihai Sain

arch/arm/boot/dts/microchip/at91-sama7g54_curiosity.dts

@@ -369,6 +369,38 @@
 		spi-tx-bus-width = <4>;
 		spi-rx-bus-width = <4>;
 		m25p,fast-read;
+		label = "at91-qspi";
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			at91bootstrap@0 {
+				label = "qspi1: at91bootstrap";
+				reg = <0x0 0x40000>;
+			};
+
+			bootloader@40000 {
+				label = "qspi1: u-boot";
+				reg = <0x40000 0x100000>;
+			};
+
+			bootloaderenv@140000 {
+				label = "qspi1: u-boot env";
+				reg = <0x140000 0x40000>;
+			};
+
+			dtb@180000 {
+				label = "qspi1: device tree";
+				reg = <0x180000 0x80000>;
+			};
+
+			kernel@200000 {
+				label = "qspi1: kernel";
+				reg = <0x200000 0x600000>;
+			};
+		};
 	};
 };