systemc: prevent from invalidate callback re-registration

Remove the redundant callback to save the memory.

Change-Id: Iafa6ada06f62ac2928a580c25ebbcbbe3f195670
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64474
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Earl Ou <shunhsingou@google.com>
2 files changed