Don't read from disk when checking volume type

Should be faster than relying on the OS to cache the magic words.
Also gets rid of the odd recursive call in VolumeDirectory.

Source/Core/DiscIO/VolumeWiiCrypted.cpp

@@ -227,6 +227,11 @@ std::string CVolumeWiiCrypted::GetApploaderDate() const
 	return date;
 }
 
+bool CVolumeWiiCrypted::IsWiiDisc() const
+{
+	return true;
+}
+
 u64 CVolumeWiiCrypted::GetSize() const
 {
 	if (m_pReader)