PowerPC: Move MMU-specifics from PowerPC.h to MMU.h

PowerPC.h at this point is pretty much a general glob of stuff, and it's
unfortunate, since it means pulling in a lot of unrelated header
dependencies and a bunch of other things that don't need to be seen by
things that just want to read memory.

Breaking this out into its own header keeps all the MMU-related stuff
together and also limits the amount of header dependencies being
included (the primary motivation for this being the former reason).

Source/Core/DolphinQt2/Debugger/CodeViewWidget.cpp

@@ -22,6 +22,7 @@
 #include "Common/StringUtil.h"
 #include "Core/Core.h"
 #include "Core/Debugger/PPCDebugInterface.h"
+#include "Core/PowerPC/MMU.h"
 #include "Core/PowerPC/PPCAnalyst.h"
 #include "Core/PowerPC/PPCSymbolDB.h"
 #include "Core/PowerPC/PowerPC.h"

Source/Core/DolphinQt2/Debugger/CodeWidget.cpp

@@ -19,6 +19,7 @@
 #include "Core/Core.h"
 #include "Core/Debugger/Debugger_SymbolMap.h"
 #include "Core/HW/CPU.h"
+#include "Core/PowerPC/MMU.h"
 #include "Core/PowerPC/PPCSymbolDB.h"
 #include "Core/PowerPC/PowerPC.h"
 #include "DolphinQt2/Host.h"

Source/Core/DolphinQt2/Debugger/MemoryViewWidget.cpp

@@ -10,10 +10,13 @@
 #include <QMenu>
 #include <QMouseEvent>
 #include <QScrollBar>
+
+#include <cctype>
 #include <cmath>
 
 #include "Core/Core.h"
 #include "Core/PowerPC/BreakPoints.h"
+#include "Core/PowerPC/MMU.h"
 #include "Core/PowerPC/PowerPC.h"
 
 #include "DolphinQt2/QtUtils/ActionHelper.h"

Source/Core/DolphinQt2/Debugger/WatchWidget.cpp

@@ -8,6 +8,7 @@
 #include "Common/IniFile.h"
 #include "Core/ConfigManager.h"
 #include "Core/Core.h"
+#include "Core/PowerPC/MMU.h"
 #include "Core/PowerPC/PowerPC.h"
 
 #include "DolphinQt2/QtUtils/ActionHelper.h"