kern: mark KThread/KProcess.GetId() final to save virtual calls

libraries/libmesosphere/include/mesosphere/kern_k_trace.hpp

@@ -83,4 +83,4 @@ namespace ams::kern {
                 ::ams::kern::KTrace::PushRecord(::ams::kern::KTrace::Type_SvcExit1, PARAM5, PARAM6, PARAM7);                         \
             }                                                                                                                        \
         }                                                                                                                            \
-    })
+    })