Patch from: Bjorn Helgaas

This patch tweaks the 8250 ACPI namespace discovery to
        1) add support for UARTs in IO port space
        2) add support for non-extended IRQs
        3) use acpi_walk_resources() to simplify processing the
           _CRS data, and
        4) add error checking (ioremap failure, lack of MMIO
           address in _CRS).
        5) uses KERN_ERR, KERN_WARNING, etc
        6) complains if register_serial() fails (i.e., if UART_NR
           is too small)

This is one step towards eliminating blind probing for devices
on ia64.  ACPI is supposed to tell us where legacy devices are;
why not use that information?