cmCxxModuleMapper: Remove redundant path conversion callbacks

Two calls to `PathForGenerator` were applied to values returned by
`BmiGeneratorPathForModule`, that already calls `PathForGenerator`.

Source/cmCxxModuleMapper.cxx

@@ -239,8 +239,7 @@ std::set<std::string> CxxModuleUsageSeed(
     for (auto const& p : object.Provides) {
       if (auto bmi_loc = loc.BmiGeneratorPathForModule(p.LogicalName)) {
         // XXX(cxx-modules): How to support header units?
-        usages.AddReference(p.LogicalName, loc.PathForGenerator(*bmi_loc),
-                            LookupMethod::ByName);
+        usages.AddReference(p.LogicalName, *bmi_loc, LookupMethod::ByName);
       }
     }
 
@@ -268,8 +267,7 @@ std::set<std::string> CxxModuleUsageSeed(
       }
 
       if (bmi_loc) {
-        usages.AddReference(r.LogicalName, loc.PathForGenerator(*bmi_loc),
-                            r.Method);
+        usages.AddReference(r.LogicalName, *bmi_loc, r.Method);
       }
     }
   }