ACPI: processor: move acpi_get_cpuid into processor_core.c

Enumerating processors (via MADT/_MAT) belongs in the processor core,
which is always built-in, rather than living in the processor driver
which may not be built.

Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>