schemas: legacy: extract GenericSMBusMux

Unknown use-case.

Create a schema anyways for completeness sake.

Tested: Schema Validator Pass

Change-Id: I95bc4efe8feb950a66cd8e0732fe4b76faed6214
Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com>
diff --git a/schemas/legacy.json b/schemas/legacy.json
index 6945506..ae983f4 100644
--- a/schemas/legacy.json
+++ b/schemas/legacy.json
@@ -1006,6 +1006,21 @@
                 }
             }
         },
+        "GenericSMBusMux": {
+            "description": "unknown purpose",
+            "additionalProperties": false,
+            "properties": {
+                "Name": {
+                    "$ref": "#/$defs/Types/Name"
+                },
+                "Address": {
+                    "$ref": "#/$defs/Types/Address"
+                },
+                "Type": {
+                    "const": "GenericSMBusMux"
+                }
+            }
+        },
         "Aggregate": {
             "description": "Don't add additional properties to this schema. Consult README.schema for instructions on adding new Exposes element sub-schema.",
             "additionalProperties": false,
@@ -1071,7 +1086,6 @@
                         "XDPE152C4D",
                         "UCD90160",
                         "UCD90320",
-                        "GenericSMBusMux",
                         "PSM7"
                     ]
                 }