x86/dma: unify definition of pci_unmap_addr* and pci_unmap_len macros

Impact: unification of pci-dma macros and pci_32.h removal

This patch unifies the definition of the pci_unmap_addr*, pci_unmap_len*
and DECLARE_PCI_UNMAP* macros. This makes sense because the pci_unmap
functions are no longer no-ops anymore when the kernel runs with
CONFIG_DMA_API_DEBUG. Without an iommu or DMA_API_DEBUG it is a no-op on 32 bit
because the dma mapping path returns a physical address and therefore the
dma-api implementation has no internal state which needs to be destroyed with
an unmap call.
This unification also simplifies the port of x86_64 iommu drivers to 32 bit x86
and let us get rid of pci_32.h.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>