meta-openpower: prep for new override syntax

Change-Id: I5ca16c6fa7bc616bfa9bc41c4f86d32fd92b0287
Signed-off-by: Adriana Kobylak <anoo@us.ibm.com>
diff --git a/meta-openpower/recipes-phosphor/dbus/phosphor-mapper-config-native%.bbappend b/meta-openpower/recipes-phosphor/dbus/phosphor-mapper-config-native%.bbappend
index 04df973..4eb20e8 100644
--- a/meta-openpower/recipes-phosphor/dbus/phosphor-mapper-config-native%.bbappend
+++ b/meta-openpower/recipes-phosphor/dbus/phosphor-mapper-config-native%.bbappend
@@ -1 +1 @@
-PHOSPHOR_MAPPER_CONFIGS_append_df-openpower = " openpower-dbus-interfaces-mapper-config-native"
+PHOSPHOR_MAPPER_CONFIGS:append:df-openpower = " openpower-dbus-interfaces-mapper-config-native"