Update hwtable factorization

Update hwtable factorization

During hwtable factorization we should _not_ merge the entries,
as the original entries might be regular expressions. Thus they
might match more devices than the new, user-provided one.
So during factorization we should _not_ remove duplicate
entries, but rather update the new entries with the missing
defaults and scan the table backwards.
With this we'll be using the modified entries for the matching
devices _only_, leaving all others intact.

Signed-off-by: Hannes Reinecke <hare@suse.de>