Add known path of the error yaml file in base class

Change-Id: Iea12235cfd5bd01902b187ea4f6f2d6869a016e3
Signed-off-by: Marri Devender Rao <devenrao@in.ibm.com>
diff --git a/classes/phosphor-logging.bbclass b/classes/phosphor-logging.bbclass
index 18f53d4..0264b51 100644
--- a/classes/phosphor-logging.bbclass
+++ b/classes/phosphor-logging.bbclass
@@ -1 +1,2 @@
 callouts_datadir="${datadir}/phosphor-logging/callouts"
+error_yaml_dir = "${datadir}/phosphor-logging/error/yaml"