Use 8888, always, for Danganronpa's FBOs

This should fix dithering on draw (guessing) causing problems for Adreno 3xx devices.  At least someone tested, and a test that basically did this seemed to fix it.

To summarize, from my memory at least:
 * On some cards, blitting from 8888 -> 565 can cause dithering.
 * On some cards, downloading from 565 in format 8888 can cause dithering.
 * On some cards, drawing to 565 can cause dithering.

All of these presumably without dithering enabled (Danganronpa never enables dithering that I've seen.)

This also reverts #1081 because I couldn't figure out why we needed to set it twice and it just looked confusing (enable == set(true)).

@solarmystic if you could test it and let me know if it still works for you (lint roller, etc.), I'd appreciate it.

-[Unknown]
FB_READFBOMEMORY_CPU is not delcare in non-windows