By defining generic hweight*() routines

- hweight64() will be defined on all architectures
- hweight_long() will use architecture optimized hweight32() or hweight64()

I found two possible cleanups by these reasons.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>