meta-phosphor: prep for new override syntax

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I588025b614416c43aa2d053765ab53bacf890cb5
diff --git a/meta-phosphor/classes/obmc-phosphor-sdbus-service.bbclass b/meta-phosphor/classes/obmc-phosphor-sdbus-service.bbclass
index bc190d4..e4578e6 100644
--- a/meta-phosphor/classes/obmc-phosphor-sdbus-service.bbclass
+++ b/meta-phosphor/classes/obmc-phosphor-sdbus-service.bbclass
@@ -3,6 +3,6 @@
 # Class users should define DBUS_SERVICES prior to including.
 
 DEPENDS += "systemd"
-RDEPENDS_${PN} += "libsystemd"
+RDEPENDS:${PN} += "libsystemd"
 
 inherit obmc-phosphor-dbus-service