Add location order to the definition of from-reads (#2402)

Signed-off-by: Hernan Ponce de Leon <[email protected]>

appendices/memorymodel.adoc

@@ -1016,8 +1016,8 @@ value written by the first operation.
 _From-reads_ is a relation between operations, where the first operation is
 a read, the second operation is a write, and the first operation reads a
 value written earlier than the second operation in the second operation's
-scoped modification order (or the first operation reads from the initial
-value, and the second operation is any write to the same locations).
+scoped modification order or location order (or the first operation reads from
+the initial value, and the second operation is any write to the same locations).
 
 Then the implementation must: guarantee that no cycles exist in the union of
 the following relations: