By validating the checksum, we can identify if the configuration is
corrupt.  In addition, this patch writes the configuration in a short
series of block writes rather than as many individual values.
Signed-off-by: NNick Dyer <nick.dyer@itdev.co.uk>
Acked-by: NBenson Leung <bleung@chromium.org>
Acked-by: NYufeng Shen <miletus@chromium.org>
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>