Zephyr : Path to GA

[psiddh]

0. Current Blocker: CI Issue

• Zephyr job on OSS CI is broken : (See HUD)

1. Review / Cleanup this CMakeList to build ET for Zepyr
   https://github.com/BujSet/zephyr/blob/f1fd77a98050d1daa34102c9dc73eae38287427f/modules/executorch/CMakeLists.txt
   ** This is authored by someone from the community and have few workarounds in there.

2. Then add ET as Ext module, currently added as an optional module. it should be an external module
   Current Change:

• https://github.com/BujSet/zephyr/blob/f1fd77a98050d1daa34102c9dc73eae38287427f/submanifests/optional.yaml#L6-L26
  ** Note how it points to Bujji’s fork. We need to fix that too
• Proposed fix: https://docs.zephyrproject.org/latest/develop/manifest/index.html#external-projects-modules

3. Then add Samples folder
   https://github.com/BujSet/zephyr/tree/executorch-module-integration/samples/modules/executorch/arm-fvp-tutorials
   We need to undo few changes Bujji made to arm_executorch runner and clean up

4. Finally the tutorial / README should be as simple (or) equivalent as running arm FVP based setup on any other platform . It should not be any different for Zephyr.

[zingo]

PR created here #16294