unify dma_get_cache_alignment implementations

Now each architecture has the own dma_get_cache_alignment
implementation.

dma_get_cache_alignment returns the minimum DMA
alignment. Architectures defines it as ARCH_KMALLOC_MINALIGN (it's
used to make sure that malloc'ed buffer is DMA-safe; the buffer
doesn't share a cache with the others). So we can unify
dma_get_cache_alignment implementations.

This can be applied to -mm.

=
 arch/alpha/include/asm/dma-mapping.h         |    1 -
 arch/arm/include/asm/cache.h                 |    2 +-
 arch/arm/include/asm/dma-mapping.h           |    5 -----
 arch/avr32/include/asm/cache.h               |    2 +-
 arch/avr32/include/asm/dma-mapping.h         |    5 -----
 arch/blackfin/include/asm/cache.h            |    2 +-
 arch/blackfin/include/asm/dma-mapping.h      |    1 -
 arch/cris/include/asm/dma-mapping.h          |    6 ------
 arch/frv/include/asm/dma-mapping.h           |    6 ------
 arch/frv/include/asm/mem-layout.h            |    2 +-
 arch/ia64/include/asm/dma-mapping.h          |    2 --
 arch/ia64/kernel/setup.c                     |    6 ------
 arch/m68k/include/asm/cache.h                |    2 +-
 arch/m68k/include/asm/dma-mapping.h          |    5 -----
 arch/microblaze/include/asm/dma-mapping.h    |    5 -----
 arch/microblaze/include/asm/page.h           |    2 +-
 arch/mips/include/asm/dma-mapping.h          |    7 -------
 arch/mips/include/asm/mach-generic/kmalloc.h |    2 +-
 arch/mips/include/asm/mach-ip27/kmalloc.h    |    2 +-
 arch/mips/include/asm/mach-ip32/kmalloc.h    |    4 ++--
 arch/mips/include/asm/mach-tx49xx/kmalloc.h  |    2 +-
 arch/mn10300/include/asm/cache.h             |    2 +-
 arch/mn10300/include/asm/dma-mapping.h       |    6 ------
 arch/parisc/include/asm/cache.h              |    2 ++
 arch/parisc/include/asm/dma-mapping.h        |    6 ------
 arch/powerpc/include/asm/dma-mapping.h       |   15 ---------------
 arch/powerpc/include/asm/page_32.h           |    2 +-
 arch/sh/include/asm/dma-mapping.h            |    9 ---------
 arch/sh/include/asm/page.h                   |    2 +-
 arch/sparc/include/asm/dma-mapping.h         |    9 ---------
 arch/tile/include/asm/dma-mapping.h          |    7 -------
 arch/x86/include/asm/dma-mapping.h           |    7 -------
 arch/xtensa/include/asm/cache.h              |    2 +-
 arch/xtensa/include/asm/dma-mapping.h        |    6 ------
 include/linux/dma-mapping.h                  |    8 ++++++++
 include/linux/slab_def.h                     |    4 +++-
 include/linux/slob_def.h                     |    4 +++-
 include/linux/slub_def.h                     |    8 +++++---
 38 files changed, 36 insertions(+), 134 deletions(-)