Subject: natsemi: Allow users to disable workaround for DspCfg reset

The natsemi driver contains a workaround for broken hardware which can
partially reset the chip at unpredictable times, detected by checking for
spontaneous changes in the DspCfg register.  The effects of the hardware
bug appear to be variable and can range from minor problems like small
numbers of corrupted packets to major ones such as the chip becoming
non-functional.  In the case of minor problems the chip reconfiguration
required to work around the hardware can cause more problems than the bug
itself.

Since we have no way of automatically determining how badly the problem
manifests on any given system provide an option in sysfs allowing users to
disable the workaround at runtime and provides a module option to set the
default.

Signed-Off-By: Mark Brown <broonie@sirena.org.uk>

Signed-off-by: Jeff Garzik <jeff@garzik.org>