Install witherspoon fan watchdog service

This service will start on a power on and uses the busybox
watchdog app to continuously ping the watchdog device.

If other logic that is in place detects that phosphor-fan has
lost control of the fans, it will start the obmc-fan-watchdog-takeover
target, which will stop this service and expire the watchdog, pushing
the fans to high speed.  A power cycle or BMC reboot is
required to recover fan control.

An environment file is used to give the watchdog app the device
and timeout parameters.

Change-Id: I7088d3ea97beaa4922b9ad357f0ce9738e10cb22
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
5 files changed