valve: update direction enum to xyz.xxx prefix

Valve direction has been changed to enum in phosphor-dbus-interfaces as
per [1] to align it with other enum types such as chassis type. Define
the direction as enum values prefixed with xyz.xxx to align with
phosphor-dbus-interfaces definition.

[1] https://gerrit.openbmc.org/c/openbmc/phosphor-dbus-interfaces/+/77416/comment/d80be379_634271e4/

Change-Id: I4681d4f02bd711f20cf65193811acbcdf61b670a
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
diff --git a/schemas/openbmc-dbus.json b/schemas/openbmc-dbus.json
index 05d4669..8d3f834 100644
--- a/schemas/openbmc-dbus.json
+++ b/schemas/openbmc-dbus.json
@@ -177,7 +177,11 @@
                             "additionalProperties": false,
                             "properties": {
                                 "Direction": {
-                                    "enum": ["Supply", "Return", "Unknown"]
+                                    "enum": [
+                                        "xyz.openbmc_project.Inventory.Item.Valve.Direction.Supply",
+                                        "xyz.openbmc_project.Inventory.Item.Valve.Direction.Return",
+                                        "xyz.openbmc_project.Inventory.Item.Valve.Direction.Unknown"
+                                    ]
                                 },
                                 "PairName": {
                                     "description": "This property specifies the pair name for valves when they form a supply and return valve pair; otherwise, it is set to NA.",