aml-s9xx-box: bsp-cli hashing fixes

[rpardini]

aml-s9xx-box: bsp-cli hashing fixes

• aml-s9xx-box: inline bsp-cli preinst function so it's hashed together with the hook; half fixes #6817
  • this is technically cheating, but works
  • add TODO's ref the manual include'ing of files that are not hashed in the bsp-cli
• aml-s9xx-box: move files included in bsp-cli from packages/bsp/aml-s9xx-box to config/optional/boards/aml-s9xx-box/_packages/bsp-cli; fixes #6817
  • with this:
    • those files are automatically hashed by the bsp-cli hashing mechanism
    • no need to copy them manually any more