board/zynqmp/kria: update readme.txt with info about qspi.bin

This patch updates the documentation for Kria SOMs for reflashing
the new qspi.bin binary file.

The qspi.bin is a unified binary containing both the boot.bin and
u-boot.itb files for simplifying the reflashing process and also
enabling the BIRT for reflashing the qspi.bin image as either
"ImageA" or "ImageB".

Signed-off-by: Neal Frager <neal.frager@amd.com>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

board/zynqmp/kria/readme.txt

@@ -42,6 +42,7 @@ After building, you should get a tree like this:
     +-- boot.bin
     +-- boot.vfat
     +-- Image
+    +-- qspi.bin
     +-- rootfs.ext2
     +-- rootfs.ext4 -> rootfs.ext2
     +-- sdcard.img
@@ -80,39 +81,28 @@ easier.
 Instructions for using these utilities to update the files
 in QSPI flash can be found on the wiki link below.
 
-https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/1641152513/Kria+K26+SOM#Boot-Firmware-Updates
+Please note that since the BIRT utility requires a single file
+for flashing, the qspi.bin should be used as either ImageA or
+ImageB.  The qspi.bin is a unified binary containing both the
+boot.bin and u-boot.itb files in a single binary.
+
+https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/1641152513/Kria+SOMs+Starter+Kits#Boot-FW-Update-Process
 
 Additionally, it is possible to use u-boot for updating the
-QSPI with new boot.bin and u-boot.itb images with the u-boot
-commands below.
+QSPI with new qspi.bin image with the u-boot commands below.
 
 KV260 Flashing Instructions:
-Flashing u-boot.itb:
-    $ sf probe
-    $ fatload mmc 1 0x1000000 u-boot.itb
-    $ sf erase 0x280000 +$filesize
-    $ sf write 0x1000000 0x280000 $filesize
-
-Flashing boot.bin:
     $ sf probe
-    $ fatload mmc 1 0x1000000 boot.bin
+    $ fatload mmc 1 0x1000000 qspi.bin
     $ sf erase 0x200000 +$filesize
     $ sf write 0x1000000 0x200000 $filesize
 
 KD240 / KR260 Flashing Instructions:
-Flashing u-boot.itb:
-    $ usb start
-    $ sf probe
-    $ fatload usb 0 0x1000000 u-boot.itb
-    $ sf erase 0x280000 +$filesize
-    $ sf write 0x1000000 0x280000 $filesize
-
-Flashing boot.bin:
     $ usb start
     $ sf probe
-    $ fatload usb 0 0x1000000 boot.bin
+    $ fatload usb 0 0x1000000 qspi.bin
     $ sf erase 0x200000 +$filesize
     $ sf write 0x1000000 0x200000 $filesize
 
 It is possible to boot the Buildroot generated SD card image without
-updating the QSPI boot.bin image, so this is an optional step.
+updating the QSPI qspi.bin image, so this is an optional step.