ACPI: IA64: fix %ll build warnings

acpi_integer is 64-bits on all platforms, and so was defined as a u64.

i386 and x86_64 define u64 as unsigned long long.
ia64 defines u64 as long.

While these are all 64-bits, the kernel build warns about formating
a "long" with %ll:

drivers/ata/libata-acpi.c:176: warning: long long unsigned int format, acpi_integer arg (arg 5)

So skip using "u64" and define acpi_integer as "unsigned long long"
to make gcc happy with %ll.

Signed-off-by: Len Brown <len.brown@intel.com>