[libsigrokdecode/f19] (3 commits) ...Adresss recommendations from review

[Alex G]

Summary of changes:

  6bc35a4... Initial import (#865977). (*)
  0da78c9... Add files missing from initial import (*)
  52b4e3b... Adresss recommendations from review (*)

(*) This commit already existed in another branch; no separate mail sent