Fix loading DLC using IOCTL_ES_OPENTITLECONTENT & /dev/es state save.
(Intertwined enough that's it's easier to do in one patch.)
(1) /dev/es did not support state save, which could cause crashes and
incorrect behavior after loading.
(2) NANDContentLoader tried to read all of a title's contents into
memory when it was first opened. Two issues:
- If any contents were missing, it bailed out. However, with DLC,
only some of the contents may be downloaded, as determined by the
permission bits in the ticket. Instead, return an appropriate error
when a content is accessed that doesn't exist on the filesystem
(don't bother checking the permission bits though).
- Everything was loaded into memory - even if it consisted of 3 GB of
songs, which caused Dolphin to lag out for quite a while (and would
fail on 32-bit). Instead, open content on demand.
