witherspoon: Remove `witherspoon` naming from fan watchdog

Remove the use of `witherspoon` in the names of the recipe, config
files, and services of the fan watchdog. This is in prep to use this
same fan watchdog on other machines within meta-ibm that have different
configurations.

Tested:
    Witherspoon image matches image prior to change
    Flash image to Witherspoon and force watchdog to trip

(From meta-ibm rev: 80f819efec08f7cc7de6988f64c0c77e20990f05)

Change-Id: I77295974397cd4903cd1a723b9ef97ee744d2557
Signed-off-by: Matthew Barth <msbarth@us.ibm.com>
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>