Add SPI driver code for the legacy SPI flash controller. Enable erase
and write support allowing coreboot to save non-volatile data into
the SPI flash.
TEST=Build and run on Galileo Gen2.
Change-Id: I8f38c955d7c42a1e58728c728d0cecc36556de5c
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/20231
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
