storage metric: add generic path

Add the generic path for the storage metric and the specific paths will
be relative to it, which will be computed at run-time. Delete the
TmpStorage path from the interface file.

Change-Id: Iaa82443c432b2e6c8d4a79aaa917d1ba88eec850
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 6b9ca9b..23973da 100644
--- a/yaml/xyz/openbmc_project/Metric/Value.interface.yaml
+++ b/yaml/xyz/openbmc_project/Metric/Value.interface.yaml
@@ -93,14 +93,18 @@
             description: >
                 The total CPU utilization.
             value: cpu/total
+          - name: Storage
+            description: >
+                The different types of available storage, such as tmp, var etc.
+                Each storage type will have path relative to storage/, for
+                example storage/tmp for temporary storage.
+            value: storage
           - name: ReadWriteStorage
             description: >
-                The available read write storage.
+                The available read write storage. This storage path has been
+                explicity added to the interface file as it gets used in BMCWeb
+                and free storage metric gets exposed via Redfish.
             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