soc/intel: 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: Id3f05a2ea6eb5e31ca607861973d96b507208115
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/19778
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>
5 files changed