drivers: kscan: Convert drivers to new DT device macros

Convert kscan drivers from:

    DEVICE_AND_API_INIT -> DEVICE_DT_INST_DEFINE
    DEVICE_GET -> DEVICE_DT_INST_GET
    DEVICE_DECLARE -> DEVICE_DT_INST_DECLARE

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>