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

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>