sim: allow specifying remote gdb port for each workload

In a platform with multiple systems, we may want to specify the
remote gdb port for each system. This change makes it
possible to specify the port number at each Workload instance.

Change-Id: I755b3960ee920ae5289819aa05d98902614a5615
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65151
Maintainer: Earl Ou <shunhsingou@google.com>
Reviewed-by: Yu-hsin Wang <yuhsingw@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/sim/debug.hh

@@ -60,10 +60,6 @@ void takeCheckpoint(Tick when);
  */
 void eventqDump();
 
-int getRemoteGDBPort();
-// Remote gdb base port.  0 disables remote gdb.
-void setRemoteGDBPort(int port);
-
 } // namespace gem5
 
 #endif // __SIM_DEBUG_HH__