dma-mapping: add asm-generic/dma-mapping-common.h

We unified x86 and IA64's handling of multiple dma mapping operations
(struct dma_map_ops in linux/dma-mapping.h) so we can remove duplication
in their arch/include/asm/dma-mapping.h.

This patchset adds include/asm-generic/dma-mapping-common.h that provides
some generic dma mapping function definitions for the users of struct
dma_map_ops.  This enables us to remove about 100 lines.  This also
enables us to easily add CONFIG_DMA_API_DEBUG support, which only x86
supports for now.  The 4th patch adds CONFIG_DMA_API_DEBUG support to IA64
by adding only 8 lines.

This patch:

This header file provides some mapping function definitions that the users
of struct dma_map_ops can use.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Joerg Roedel <joerg.roedel@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>