This adds Fujitsu-Siemens AMILO Pro 8210 support to wistron_btns driver.

Functions are very similar to already supported AMILO Pro 3505, but 8210
has WIFI led.

Such functionality is needed to enable WiFi under Linux on 8210 when it
cold boots with hardware rfkill enabled, without booting another operating
system or running custom utility that calls appropriate BIOS function.
Signed-off-by: Jakub Bogusz <qboosh@pld-linux.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>