systemc: Suppress a spurious clang warning in the systemc headers.

Change-Id: Ife2251d370133383debda9b0439cb84eca80978d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23126
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/systemc/ext/tlm_core/2/sockets/initiator_socket.hh

@@ -169,6 +169,9 @@ class tlm_base_initiator_socket :
 
   protected:
     export_type m_export;
+
+  private:
+    using port_type::bind;
 };
 
 //