Improved bitrev with approach suggested by Jens Arnold, gives 0.5%-1% speedup for tremor decoding on sansa c200 (PP) and a tiny speedup on coldfire as well

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@24102 a1c6a512-1295-4272-9138-f99709370657
1 file changed