libgpiod: Upgrade to v1.6.4 and add recipe for v2.0
This backports the latest libgpiod recipes from meta-oe master. The new libgpiod v2 includes major changes and improvements and might be required in certain use cases.
For now the default remains v1.6 while someone who needs the v2 can
set PREFERRED_VERSION_libgpiod = "2.0"
.
See https://git.kontron-electronics.de/sw/ked/plan/plan-yocto/-/issues/1154#note_41481 for a use case.
Edited by Frieder Schrempf