health_metric: add path for tmp storage

Add the path for temporary storage to be used in HealthMonitor.

Change-Id: I58792286c872846a7b8d71fed11190de852025d6
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/yaml/xyz/openbmc_project/Metric/Value.interface.yaml b/yaml/xyz/openbmc_project/Metric/Value.interface.yaml
index bd01cac..6b9ca9b 100644
--- a/yaml/xyz/openbmc_project/Metric/Value.interface.yaml
+++ b/yaml/xyz/openbmc_project/Metric/Value.interface.yaml
@@ -97,6 +97,10 @@
             description: >
                 The available read write storage.
             value: storage/rw
+          - name: TmpStorage
+            description: >
+                The available temporary storage.
+            value: storage/tmp
           - name: RebootCount
             description: >
                 Reboot statistic to track number of times device rebooted