thinkpad-acpi: handle some new HKEY 0x60xx events

thinkpad-acpi: handle some new HKEY 0x60xx events

Handle some user interface events from the newer Lenovo models.  We are likely
to do something smart with these events in the future, for now, hide the ones
we are already certain about from the user and userspace both.

* Events 0x6000 and 0x6005 are key-related.  0x6005 is not properly identified
  yet.  Ignore these events, and do not report them.

* Event 0x6040 has not been properly identified yet, and we don't know if it
  is important (looks like it isn't, but still...).  Keep reporting it.

* Change the message the driver outputs on unknown 0x6xxx events, as all
  recent events are not related to thermal alarms.  Degrade log level from
  ALERT to WARNING.

Thanks to all users who reported these events or asked about them in a number
of mailing lists.  Your help is highly appreciated, even if I did took a lot of
time to act on them.  For that I apologise.

I will list those that identified the reasons for the events as "reported-by",
and I apologise in advance if I leave anyone out: it was not done on purpose, I
made the mistake of not properly tagging all event report emails separately,
and might have missed some.

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Reported-by: Markus Malkusch <markus@malkusch.de>
Reported-by: Peter Giles <g1l3sp@gmail.com>