The change in the size of the hotkey mask, the hability to report the keys
that use the higher bits, and the addition of the hotkey_radio_sw attribute
are important enough features to warrant increasing the minor field of the
sysfs interface version.

Also, document a bit better how and when the thinkpad-acpi sysfs interface
version will be updated.
Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>