gpio: fix data race in EasyDriver

[gen2thomas]

Solved issues and/or description of the change

data race in EasyDriver found by go test -race - fixed by rework of driver and tests

this partially fix #1017

Manual test

none

Checklist

• The PR's target branch is 'hybridgroup:dev'
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes (e.g. by run make test)
• No linter errors exist locally (e.g. by run make fmt_check)
• I have performed a self-review of my own code