[RFC PATCH] support Thinkpad X1 Carbon's adaptive keyboard

[Shuduo Sang]

Hi all,

We are working together with Lenovo to enable thinkpad X1 Carbon's
fancy feature, Adaptive Keyboard[1] for Linux. Adaptive keyboard has
five modes on Windows including Home mode, Web browser mode, Web
conference mode, Function mode and Lay-flat mode. We enabled Home
mode and Function mode currently. Will try to find out how to enable
other modes later. Please review and comment attached patch.

Thanks,
Shuduo

[1]:http://shop.lenovo.com/us/en/laptops/thinkpad/x-series/x1-carbon/#features