meta-phosphor: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I588025b614416c43aa2d053765ab53bacf890cb5
diff --git a/meta-phosphor/recipes-phosphor/video/fbterm_git.bb b/meta-phosphor/recipes-phosphor/video/fbterm_git.bb
index 0c171dd..57e2174 100644
--- a/meta-phosphor/recipes-phosphor/video/fbterm_git.bb
+++ b/meta-phosphor/recipes-phosphor/video/fbterm_git.bb
@@ -25,5 +25,5 @@
     install -m 0644 ${WORKDIR}/fb.modes ${D}${sysconfdir}/
 }
 
-SYSTEMD_SERVICE_${PN} += "fbterm.service"
+SYSTEMD_SERVICE:${PN} += "fbterm.service"
 SYSTEMD_ENVIRONMENT_FILE_${PN} += "fbterm"