dell-wmi: Add information about other WMI event codes

ACPI DSDT tables have defined other WMI codes, but does not contain any
description when those codes are emitted. Some other codes can be found in
logs on internet. In this patch are all which I saw, but lot of them are
not tested properly (e.g. for duplicate events with AT keyboard). Now we
have all WMI event codes at one place and in future after proper testing
those codes can be correctly enabled or disabled...

Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Tested-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Michał Kępień <kernel@kempniu.pl>
Tested-by: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>