[coreboot-gerrit] Patch merged into coreboot/master: spi: Get rid of SPI_ATOMIC_SEQUENCING

the following patch was just integrated into master:
commit c2973d196d1224a1253478dc29d5f8fa004eaab8
Author: Furquan Shaikh 
Date:   Tue Nov 29 22:07:42 2016 -0800

spi: Get rid of SPI_ATOMIC_SEQUENCING

SPI_ATOMIC_SEQUENCING was added to accomodate spi flash controllers with
    the ability to perform tx and rx of flash command and response at the
    same time. Instead of introducing this notion at SPI flash driver layer,
    clean up the interface to SPI used by flash.

Flash uses a command-response kind of communication. Thus, even though
    SPI is duplex, flash command needs to be sent out on SPI bus and then
    flash response should be received on the bus. Some specialized x86
    flash controllers are capable of handling command and response in a
    single transaction.

In order to support all the varied cases:
    1. Add spi_xfer_vector that takes as input a vector of SPI operations
    and calls back into SPI controller driver to process these operations.
    2. In order to accomodate flash command-response model, use two vectors
    while calling into spi_xfer_vector -- one with dout set to
    non-NULL(command) and other with din set to non-NULL(response).
    3. For specialized SPI flash controllers combine two successive vectors
    if the transactions look like a command-response pair.
    4. Provide helper functions for common cases like supporting only 2
    vectors at a time, supporting n vectors at a time, default vector
    operation to cycle through all SPI op vectors one by one.

BUG=chrome-os-partner:59832
    BRANCH=None
    TEST=Compiles successfully

Change-Id: I4c9e78c585ad95c40c0d5af078ff8251da286236
    Signed-off-by: Furquan Shaikh 
    Reviewed-on: https://review.coreboot.org/17681
    Tested-by: build bot (Jenkins)
    Reviewed-by: Aaron Durbin

See https://review.coreboot.org/17681 for details.

-gerrit