ia64/PCI: Remove unused 'addr' and fix build warning

Ever since commit 240504ad ("ia64/PCI: Keep CPU physical (not
virtual) addresses in shadow ROM resource") 'addr' has been unused,
resulting in the following compiler warning,

  arch/ia64/sn/kernel/io_acpi_init.c: In function 'sn_acpi_slot_fixup':
  arch/ia64/sn/kernel/io_acpi_init.c:429:16: warning: unused variable 'addr' [-Wunused-variable]
    void __iomem *addr;
                ^

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Tony Luck <tony.luck@intel.com>