fix misspelling lpm -> lmp in content.md

suggesting that 'lpm-manifest repository' is wrong, it should be lmp-manifest repository like the repo itself:
Arduino Linux microPlatform Manifest
https://github.com/arduino/lmp-manifest

Author: e1ke

content/hardware/04.pro/boards/portenta-x8/tutorials/09.image-flashing/content.md

@@ -37,7 +37,7 @@ In this tutorial, you will learn how to manually flash your Portenta X8 with the
 
 Go to [Arduino Download repository](https://downloads.arduino.cc/portentax8image/image-latest.tar.gz), and a compressed `.tar.gz` with the latest version of all the required OS image files will be there to download.
 
-![lpm-manifest repository overview](assets/lpm-manifest-overview.png)
+![lmp-manifest repository overview](assets/lmp-manifest-overview.png)
 
 Please extract the files after you have downloaded the compressed file. The extracted contents have the following structure.