iot2050: Add watchdog start to bootcmd

Allows run-time control over watchdog auto-start and the timeout via
setting the environment variable watchdog_timeout_ms. A value of zero
means "do not start". Use CONFIG_WATCHDOG_TIMEOUT_MSECS as initial value
and this to zero by default. Users can then enable the watchdog once the
use and OS which picks it up during boot.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
3 files changed