dma-mapping: alpha: use include/linux/pci-dma-compat.h

This converts Alpha to use include/linux/pci-dma-compat.h.  Alpha is the
only architecutre that implements the PCI DMA API in the own way.  That
makes it difficult to implement the generic DMA API via the PCI bus
specific DMA API.

The generic DMA API calls the PCI DMA API implementation in
arch/alpha/kernel/pci_iommu.c on non Jensen systems.  It calls the DMA API
in arch/alpha/kernel/pci-noop.c on Jensen systems.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Greg KH <greg@kroah.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>