Revert "Implement status register read/write callbacks in flash struct"

This reverts commit 953967b97cd6a02f6c7bb75a1dffed24ce3d1710.

We seem to have overlooked a few things:
https://bugs.chromium.org/p/chromium/issues/detail?id=588592
https://code.google.com/p/chrome-os-partner/issues/detail?id=50429

BUG=chromium:588592
Change-Id: Ibd38281cfafbcbc9988b2bd0d2134aab09239d6d
Reviewed-on: https://chromium-review.googlesource.com/329135
Commit-Ready: David Hendricks <dhendrix@chromium.org>
Tested-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: David Hendricks <dhendrix@chromium.org>
Reviewed-by: danny chan <dchan@chromium.org>
(cherry picked from commit 3d3b3994ffef79d44cbf819c188873b2bf55deff)
Reviewed-on: https://chromium-review.googlesource.com/329245
Commit-Queue: David Hendricks <dhendrix@chromium.org>
8 files changed