misc: Implement the Base SystemC Module as an sc_channel.

Implementing the Module as an sc_channel allows derived classes to provide
SystemC interfaces. Other SystemC modules can connect to these interfaces.
This meachanism can be used to control gem5 and acces gem5 components from
within arbitrary SystemC moduels. Since sc_channel is derived from
sc_module, this patch does not break compatibility with existing code.

Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

util/systemc/sc_module.cc

@@ -43,6 +43,7 @@
  *          Steve Reinhardt
  *          Andrew Bardsley
  *          Matthias Jung
+ *          Christian Menard
  */
 
 /**
@@ -77,7 +78,7 @@ setTickFrequency()
     ::setClockFrequency(1000000000000);
 }
 
-Module::Module(sc_core::sc_module_name name) : sc_core::sc_module(name),
+Module::Module(sc_core::sc_module_name name) : sc_core::sc_channel(name),
     in_simulate(false)
 {
     SC_METHOD(eventLoop);

util/systemc/sc_module.hh

@@ -42,6 +42,7 @@
  * Authors: Nathan Binkert
  *          Steve Reinhardt
  *          Andrew Bardsley
+ *          Christian Menard
  */
 
 /**
@@ -83,7 +84,7 @@ namespace Gem5SystemC
  *  This functionality is wrapped in an sc_module as its intended that
  *  the a class representing top level simulation control should be derived
  *  from this class. */
-class Module : public sc_core::sc_module
+class Module : public sc_core::sc_channel
 {
   protected:
     /** Event to trigger (via. ::notify) for event scheduling from