cable: add CableTypeDescription

Add the CableTypeDescription property, for displaying in user
interfaces.

Change-Id: Ie891ce45470a1504624b61dc59f243be755fa9b7
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml b/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
index 8d4a774..d2f32a2 100644
--- a/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
+++ b/yaml/xyz/openbmc_project/Inventory/Item/Cable.interface.yaml
@@ -8,3 +8,12 @@
       description: >
           The length of the cable in meters.  The default value of NaN
           represents a cable of unknown length.
+    - name: CableTypeDescription
+      type: string
+      default: ""
+      description: >
+          A free form, implementation defined string used to provide the type
+          of a cable, such as optical or copper.  The cable type can be shown
+          in user interfaces but this field should not be used for programmatic
+          interrogation of a cable beyond ignoring the default value of the
+          empty string.