hwdb: merge atkbd into platform matches

Currently, we always run
  hwdb 'keyboard:name:$attr{name}:$attr{[dmi/id]modalias}'
as last step to match keyboards. Therefore, if nothing else matched so
far, we still try the device-name+dmi combination.

However, we have a special atkbd rule which is only run for atkbd as:
  hwdb 'keyboard:$attr{[dmi/id]modalias}'

This is redundant, as we already pass the same information to hwdb in the
last fallback step.

This patch converts the hwdb "keyboard:dmi:*" matches to
"keyboard:name:*:dmi:*" matches and drops the redundant rule.