At the system boot time we need enable watchdog reset, otherwise after
the watchdog is timeout it cannot reset the SoC. We need set the bit 0
and bit 16 together, the bit 16 is mask bit so after set bit 16 we have
permission to operate bit 0 and bit 0 is watchdog reset enabling bit.
Signed-off-by: Leo Yan <leo.yan@linaro.org>