radv: refactor physical device properties
Based on ANV. This removes a bunch of duplicated code for properties. Fixes: 1b8d99e2 ("radv: bump conformance version to 1.2.0.0") Signed-off-by:Samuel Pitoiset <samuel.pitoiset@gmail.com> Reviewed-by:
Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl> Tested-by: Marge Bot <!3626> Part-of: <!3626>