soc/rockchip: Move spi driver to use spi_bus_map
This is in preparation to get rid of the strong spi_setup_slave
implemented by different platforms.
BUG=b:
38430839
Change-Id: I66b1b9635ece2381f62f2a9d6f5744d639d59163
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/19771
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>