dm: exynos: cros_ec: Move cros_ec_spi to driver model

Adjust this driver to use driver model and move smdk5420 boards over to
use it.

Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
2 files changed