X86: Bring the South Bridge device into dev/x86 and get rid of south_bridge directory.

--HG--
rename : src/dev/x86/south_bridge/SouthBridge.py => src/dev/x86/SouthBridge.py
rename : src/dev/x86/south_bridge/south_bridge.cc => src/dev/x86/south_bridge.cc
rename : src/dev/x86/south_bridge/south_bridge.hh => src/dev/x86/south_bridge.hh

src/dev/x86/SConscript

@@ -34,6 +34,9 @@ if env['FULL_SYSTEM'] and env['TARGET_ISA'] == 'x86':
     SimObject('PC.py')
     Source('pc.cc')
 
+    SimObject('SouthBridge.py')
+    Source('south_bridge.cc')
+
     SimObject('Cmos.py')
     Source('cmos.cc')
     TraceFlag('CMOS', 'Accesses to CMOS devices')