Add Wii DVD integrity checking to Dolphin

This allows users to easily check whether their Wii dump is corrupted or not
using the Dolphin properties window. Right click on a game, Properties,
Filesystem tab, then right click on the game partition and select "Check
partition integrity".

This may have some false negatives due to the unused clusters heuristic (see
the comment in VolumeWiiCrypted.cpp). False positives are unlikely.

Source/Core/DiscIO/Src/VolumeWiiCrypted.h

@@ -43,6 +43,9 @@ public:
 	ECountry GetCountry() const;
 	u64 GetSize() const;
 
+	bool SupportsIntegrityCheck() const { return true; }
+	bool CheckIntegrity() const;
+
 private:
 	IBlobReader* m_pReader;