Make it so createAtrac() can return an error.

It doesn't yet, but if it's out of IDs, it should.
Implement sceAtracReinit(), reuse atracIDs.

The same way tests show the PSP does.  Fixes Ridge Racer mini loading
game when you try to play too long.
Correctly savestate the atrac ids.
Oops, dumb typo.
Fix return on atrac release, fix deinit/reinit.
Merge pull request #2313 from unknownbrackets/atrac-minor

Manage atrac IDs like the PSP does per tests