ns run from different CPUs, it's
in theory possible for the writes to be interleaved, which would be
disastrous for this driver.

At the very least, we need an mmiowb() before releasing the lock, but
since it seems desirable for the watchdog timer to be actually stopped
or reset when these functions return, read the lock register to force
the writes out.

Signed-off-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>