s2mk2: added static info for buttons
s2mk2: added static info for buttons

Device is now fully populated, with the exception of the encoder
press functionality, which is not yet easily mapped to the UI.

Signed-off-by: Harry van Haaren <6e1296516ee88185cd60d9725251227ece1af74d@gmail.com>

openAVproductions/openAV-Ctlra