wspoon: Add machine overrides to hwmon devices

In preparation for additional systems under hte witherspoon layer, add
machine overrides to the hwmon devices and service configurations. This
allows additional machines' phosphor-hwmon configurations to be placed
in this layer.

Tested:
    Witherspoon phosphor-hwmon image still contains all device configs &
    services to be installed.

Change-Id: I57d49a8a1ac93205a2281014a034f88c3f75d0ac
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
15 files changed