Patch merged into coreboot/master: drivers/spi: provide optional implementation of boot_device_rw()

the following patch was just integrated into master:
commit 6f1155916a8b2f5409d0992963a1c16178794a48
Author: Aaron Durbin 
Date:   Thu Aug 11 18:24:54 2016 -0500

drivers/spi: provide optional implementation of boot_device_rw()

On many x86 platforms the boot device is SPI which is memory
    mapped. However, in order to write to the boot device one needs
    to use the SPI api. Therefore, provide a common implementation
    of boot_device_rw() which has no mmap() functionality. It only
    reads, writes, and erases. This will be used in the existing
    infrastructure but in a SPI agnostic way.

Two options are added:
    1. BOOT_DEVICE_SPI_FLASH_RW_NOMMAP
    2. BOOT_DEVICE_SPI_FLASH_RW_NOMMAP_EARLY

The former is auto-selected when COMMON_CBFS_SPI_WRAPPER is not
    selected. The latter can be used to include the implementation
    in the early stages such as bootblock, verstage, and romstage.

BUG=chrome-os-partner:56151

Change-Id: I2aa75f88409309e3f9b9bd79b52d27c0061139c8
    Signed-off-by: Aaron Durbin 
    Reviewed-on: https://review.coreboot.org/16200
    Tested-by: build bot (Jenkins)
    Reviewed-by: Furquan Shaikh 
    Reviewed-by: Martin Roth

See https://review.coreboot.org/16200 for details.

-gerrit