[MIPS] Alchemy: Fix PCI-memory access

[MIPS] Alchemy:  Fix PCI-memory access

    The problem was introduced in 2.6.18.3 with the casting of some
    36bit-defines (PCI memory) in au1000.h to resource_size_t which may be
    u32 or u64 depending on the experimental CONFIG_RESOURCES_64BIT.

    With unset CONFIG_RESOURCES_64BIT, the pci-memory cannot be accessed
    because the ioremap in arch/mips/au1000/common/pci.c already used the
    truncated addresses.
    With set CONFIG_RESOURCES_64BIT, things get even worse, because PCI-scan
    aborts, due to resource conflict: request_resource() in arch/mips/pci/pci.c
    fails because the maximum iomem-address is 0xffffffff (32bit) but the
    pci-memory-start-address is 0x440000000 (36bit).

    To get pci working again, I propose the following patch:

    1. remove the resource_size_t-casting from au1000.h again
    2. make the casting in arch/mips/au1000/common/pci.c (it's allowed and
    necessary here. The 36bit-handling will be done in __fixup_bigphys_addr).

    With this patch pci works again like in 2.6.18.2, the gcc-compile warnings
    in pci.c are gone and it doesn't depend on CONFIG_EXPERIMENTAL.

    Signed-off-by: Alexander Bigga <ab@mycable.de>
    Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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