systemc: Add an elaboration_done method to sc_simcontext.

The TLM headers rely on this non-standard function.

Change-Id: Iaedec35f1f363dcf3e1fcdb58a74eb2cdc05ddc0
Reviewed-on: https://gem5-review.googlesource.com/c/15061
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>

src/systemc/ext/core/sc_simcontext.hh

@@ -44,6 +44,9 @@ class sc_simcontext
     sc_curr_proc_handle get_curr_proc_info();
     sc_object *first_object();
     sc_object *next_object();
+
+    // Used by TLM.
+    bool elaboration_done();
 };
 
 sc_simcontext *sc_get_curr_simcontext();