[PATCH] doc: board: xilinx: zynq.rst: add description how to flash a SD card

[Johannes Krottmayer <krjdev@gmail.com>]

Add a short description in the ZYNQ documentation how to prepare a SD card and 
copy the related images to SD card.

I think, it's necessary for the documentation to avoid such user questions
(like mine) in this list.

Okay?

Signed-off-by: Johannes Krottmayer <krjdev@gmail.com>
---
 doc/board/xilinx/zynq.rst | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/doc/board/xilinx/zynq.rst b/doc/board/xilinx/zynq.rst
index 6a09df1d15..e5f002af85 100644
--- a/doc/board/xilinx/zynq.rst
+++ b/doc/board/xilinx/zynq.rst
@@ -60,6 +60,25 @@ SLCR bootmode register Bit[3:0] values
 "modeboot" variable can assign any of "norboot", "sdboot" or "jtagboot"
 bootmode strings at runtime.
 
+Flashing
+--------
+
+SD Card
+^^^^^^^
+
+To write an image that boots from a SD card first create a FAT32 partition
+and a FAT32 filesystem on the SD card::
+
+        sudo fdisk /dev/sdx
+        sudo mkfs.vfat -F 32 /dev/sdx1
+
+Mount the SD card and copy the SPL and U-Boot to the root directory of the
+SD card::
+
+        sudo mount -t vfat /dev/sdx /mnt
+        sudo cp spl/boot.bin /mnt
+        sudo cp u-boot.img /mnt
+
 Mainline status
 ---------------
 
-- 
2.26.2