DVDInterface: Translate Wii partition offsets for timing purposes

Until now, Dolphin has been using the wrong values
for calculating DVD timing for decrypted Wii reads
(which Wii games essentially always use).

Source/Core/DiscIO/VolumeWiiCrypted.cpp

@@ -140,6 +140,12 @@ std::vector<u8> CVolumeWiiCrypted::GetTMD() const
   return buffer;
 }
 
+u64 CVolumeWiiCrypted::PartitionOffsetToRawOffset(u64 offset) const
+{
+  return m_VolumeOffset + m_dataOffset + (offset / BLOCK_DATA_SIZE * BLOCK_TOTAL_SIZE) +
+         (offset % BLOCK_DATA_SIZE);
+}
+
 std::string CVolumeWiiCrypted::GetGameID() const
 {
   if (m_pReader == nullptr)