util: Fix gem5_within_systemc and tlm coupling

Adapt the code to changes introduced with commits 3fb9139 and 392c1ce.

Jira Issue: https://gem5.atlassian.net/browse/GEM5-874

Change-Id: I0023157f1a2e5935f624c0a12e61f6b3e0d98b97
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39215
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

util/systemc/gem5_within_systemc/sc_module.cc

@@ -71,6 +71,7 @@ void
 setTickFrequency()
 {
     ::setClockFrequency(1000000000000);
+    ::fixClockFrequency();
 }
 
 Module::Module(sc_core::sc_module_name name) : sc_core::sc_channel(name),