classes-dbus: General refactoring

Take the more idiomatic approach of iterating on
DBUS_PACKAGES to find files.

Change-Id: I7656316b839f666bd1b25b757bef2c14a2cee326
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-phosphor/dbus-perms/dbus-perms.bb b/common/recipes-phosphor/dbus-perms/dbus-perms.bb
index c7b7884..c929d74 100644
--- a/common/recipes-phosphor/dbus-perms/dbus-perms.bb
+++ b/common/recipes-phosphor/dbus-perms/dbus-perms.bb
@@ -7,6 +7,4 @@
 inherit obmc-phosphor-license
 inherit obmc-phosphor-dbus-service
 
-DBUS_SERVICES += " \
-        org.openbmc \
-        "
+DBUS_SERVICE_${PN} += "org.openbmc"