generic bitops

This is 3rd trial. I hope this patch series will be added to -mm tree.
And I would like to see what it breaks.

Changes since previous version:
- s/__inline__/inline/
- s/__const__/const/
- cleanup test_le_bit()
- hweight() speedup
- out of line hweight*()
- out of line find_*_bit()
- out of line generic_find_next_zero_le_bit()
- fix arch bitops.h for ia64 and alpha
- add hweight*() related cleanups

Boot testes on:
- i386
- ppc

Cross compiled on:
- x86_64
- ia64
- alpha
- sparc
- sparc64

Large number of boilerplate bit operations which are written in C-language
are scattered around include/asm-*/bitops.h.
This patch series gathers them into include/asm-generic/bitops/*.h .
It will be the benefit to:

- kill duplicated code and comment (about 4000 lines)
- use better C-language equivalents
- help porting new architecture 

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