thinkpad-acpi: bump up version to 0.23

thinkpad-acpi: bump up version to 0.23

Plenty of high-profile changes, so it deserves a new version number.

Features added since 0.22:
 *  Restrict unsafe LEDs
 *  New race-less brightness control strategy for IBM ThinkPads
 *  Disclose TGID of driver access from userspace (debug)
 *  Warn when deprecated functions are used

Other changes:
 *  Better debug messages in some subdrivers
 *  Removed "hotkey disable" support, since it breaks the driver
 *  Dropped "ibm-acpi" alias

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Signed-off-by: Len Brown <len.brown@intel.com>