Move common crc body to new function crc32_body() cleaup and micro
optimize crc32_body for speed and less size.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NJoakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>