correct S version requirement for medelegh

Author: Derek Hower

arch/csr/medelegh.yaml

@@ -8,5 +8,7 @@ medelegh:
   base: 32
   description: |
     Alias of the upper 32 bits of `medeleg`.
-  definedBy: S
+  definedBy:
+    name: S
+    version: ">= 1.13"
   fields: {}