Documentation update for the scx200_acb driver. Hopefully this will
help future users.

References:

[lm-sensors] Support of i2c-nscacb (April, May 2005)
  http://lists.lm-sensors.org/pipermail/lm-sensors/2005-April/011756.html
  http://lists.lm-sensors.org/pipermail/lm-sensors/2005-May/012043.html

[lm-sensors] making a geode i2c slave driver (April 2006)
  http://lists.lm-sensors.org/pipermail/lm-sensors/2006-April/015998.html

Kernel bug #6445
  http://bugzilla.kernel.org/show_bug.cgi?id=6445Signed-off-by: NJean Delvare <khali@linux-fr.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>