Add inventory manager class

Change-Id: Ib034680499f16efb842bc5074e269bb590f25fbd
diff --git a/meta-phosphor/classes/phosphor-inventory-manager.bbclass b/meta-phosphor/classes/phosphor-inventory-manager.bbclass
new file mode 100644
index 0000000..01fa372
--- /dev/null
+++ b/meta-phosphor/classes/phosphor-inventory-manager.bbclass
@@ -0,0 +1,2 @@
+base_datadir="${datadir}/phosphor-inventory-manager"
+rules_datadir="${base_datadir}/events.d"