rtnl: drop "sd_" prefix from cleanup macros

rtnl: drop "sd_" prefix from cleanup macros

The "sd_" prefix is supposed to be used on exported symbols only, and
not in the middle of names. Let's drop it from the cleanup macros hence,
to make things simpler.

The bus cleanup macros don't carry the "sd_" either, so this brings the
APIs a bit nearer.