fix duplicate yaml_dir config variable declaration and usage

yaml_dir is defined both in phosphor-dbus-interfaces.bbclass and
phosphor-obmc-yaml.bbclass pointing to different locations.

Fixed the same by removing usage of phosphor-dbus-interfaces

Also removed unused openpower-dbus-interfaces.bbclass

Change-Id: I74d06a0f7d635bd708f58611444061c6d48db858
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/meta-phosphor/common/recipes-phosphor/inventory/phosphor-inventory-manager.bb b/meta-phosphor/common/recipes-phosphor/inventory/phosphor-inventory-manager.bb
index 93cdb8c..91f34f0 100644
--- a/meta-phosphor/common/recipes-phosphor/inventory/phosphor-inventory-manager.bb
+++ b/meta-phosphor/common/recipes-phosphor/inventory/phosphor-inventory-manager.bb
@@ -7,7 +7,7 @@
 inherit autotools \
         pkgconfig \
         pythonnative \
-        phosphor-dbus-interfaces \
+        phosphor-dbus-yaml \
         phosphor-inventory-manager \
         obmc-phosphor-dbus-service