Work around a dcache issue by preventing the game from doing
something pointless.
The game's DVD read function writes 0x87654321 to the entire read
buffer and 0x12345678 to the last 4 bytes. It then calls DVDReadAsync()
and without waiting for the read to complete at all, it checks if the
last 4 bytes are still 0x12345678. If they are, then the game fails.
The check always passes on console because DVDReadAsync() calls
issueCommand(), which calls DCInvalidateRange(read_buffer) (dcbi).
Dolphin cannot emulate this without an extremely significant
performance hit.
289ed21140