Add a variant of nm_device_spec_match_list() that looks up the match
paramters from a platform link instance.

Usually, we have a NMDevice instance that we use for matching.
However, at some places (like inside the device factory's
create_device() method), we might not have a NMDevice instance
to get the match paramters.

Add an alternative form, that gets the match paramters from a platform
link instance.

The code is placed inside src/NetworkManagerUtils.c, because
src/nm-core-utils.c is supposed to be independent of platform.