Split the common keyboard scanning code out of the XEC specific driver
and use the generic code instead.
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>
Convert the XEC keyboard scanning driver from kscan to input, add the
corresponding kscan compatibility node to the current board, build test
only.
Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>