Fix sceJpegGetOutputInfo

- Return better responses for errors (should allow weird God Eater Burst saves from real PSPs to not bounce back to the titlescreen). Not sure why some God Eater Burst saves would send bad jpeg data. The data sent through sceJpeg is supposed to be a normal jpeg (ie it should be perfectly viewable in photoshop or whatever image viewer/editor). The reason it doesn't send a good, decodable jpeg should still be researched but in the meantime don't push users getting that error back to the titlescreen. Returning getYCbCrBufferSize(0, 0) on error seems like it would be more correct as well (or, at least God Eater Burst recognises that as an error unlike 0xC00...I didn't think that was right but no saves gave me bad jpeg data before).

- Fix a potential redefine if a user has JPEG_DEBUG enabled (jpegBuf). Not too sure if this would cause compiling errors, but if it would it should be fixed now. VS2012 seemed fine with it, but I'm not too sure about other compilers.