spi25: Integrate 4BA support Back port the upstream `commit f43c654a` reworked for our tree. BUG=chromium:478356 BRANCH=none TEST=still builds Change-Id: I95c12d54fcc4acfbce00e59e11d00a324cbfaf7f Signed-off-by: Edward O'Callaghan <quasisec@chromium.org> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/flashrom/+/1667513 Reviewed-by: Stefan Reinauer <reinauer@google.com>