integrate dma_ops

Hi,

This is the final integration of dma_ops between x86_64 and i386.
The final code is closer to x86_64 than to i386, which is obviously expected.

At the end, pci-dma_{32,64}.c are gone, pci-nommu_64.c is gone, and the temporary
pci-base_32.c is gone too.

This patchset received the same level of scrutiny as the others from my side:
compiled tested in at least 6 different random configs, boot tested in my hardware.

The final diffstat says:

 Documentation/feature-removal-schedule.txt |    7 
 arch/x86/kernel/Makefile                   |    9 
 arch/x86/kernel/pci-base_32.c              |   72 ---
 arch/x86/kernel/pci-dma.c                  |  524 +++++++++++++++++++++++++++++
 arch/x86/kernel/pci-dma_32.c               |  503 +++++++--------------------
 arch/x86/kernel/pci-dma_64.c               |  443 +-----------------------
 arch/x86/kernel/pci-nommu.c                |  100 +++++
 arch/x86/kernel/pci-nommu_64.c             |  140 -------
 arch/x86/mm/init_64.c                      |    4 
 include/asm-x86/dma-mapping.h              |   14 
 include/asm-x86/scatterlist.h              |    3 
 11 files changed, 832 insertions(+), 987 deletions(-)