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/chassis/obmc-host-failure-reboots.bb b/meta-phosphor/recipes-phosphor/chassis/obmc-host-failure-reboots.bb
index 490a615..84403d5 100644
--- a/meta-phosphor/recipes-phosphor/chassis/obmc-host-failure-reboots.bb
+++ b/meta-phosphor/recipes-phosphor/chassis/obmc-host-failure-reboots.bb
@@ -11,5 +11,5 @@
 INSTFMT = "host-failure-reboots@{0}.service"
 LINK_FMT = "${TMPL}:${INSTFMT}"
 
-SYSTEMD_SERVICE_${PN} += "${TMPL}"
+SYSTEMD_SERVICE:${PN} += "${TMPL}"
 SYSTEMD_LINK_${PN} += "${@compose_list(d, 'LINK_FMT', 'OBMC_HOST_INSTANCES')}"