Remove _witherspoon from bbappend files

These files are already in the meta-witherspoon subdirectory, it's
redundant to have the _witherspoon append in the bbappend files.

This allows off-shoots of the witherspoon system to easily include this
meta layer and get the witherspoon default files.

Change-Id: I40c6c842ab872c4c02bab3384bce3673a1c2d07f
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/meta-witherspoon/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend b/meta-witherspoon/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend
index 8445c83..3256e83 100644
--- a/meta-witherspoon/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend
+++ b/meta-witherspoon/recipes-phosphor/ipmi/phosphor-ipmi-config.bbappend
@@ -1,4 +1,4 @@
-FILESEXTRAPATHS_prepend_witherspoon := "${THISDIR}/${PN}:"
+FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
 
 # Calculate the auxiliary firmware revision to be updated in the dev_id.json
 # file. It is calculated from the VERSION_ID field which currently has two