Hopefully fix FS #8840 for iAudio M3, M5 and X5. Reduce greyscale update frequency on M3 in order to reduce CPU load (was >50% before, but this fix would have made it even worse).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@17621 a1c6a512-1295-4272-9138-f99709370657
3 files changed