Enable Baytrail devices in kernel builds

[Bastien Nocera]

Hey,

This driver, as discussed here:
http://article.gmane.org/gmane.linux.kernel.input/35190
got merged last year.

It's the driver for buttons integrated in Baytrail tablets, and should
make power and volume buttons work on those devices.

Furthermore, we should also enable the Baytrail SoC sound devices. There's a
number of config items for this.

You'll find both enablements in the ill-fated c72e049493b3f4f691a91722ae93f57a916d75b9 commit.

Cheers