ACPI / processor: Introduce ARCH_MIGHT_HAVE_ACPI_PDC

The use of _PDC is deprecated in ACPI 3.0 in favor of _OSC,
as ARM platform is supported only in ACPI 5.0 or higher version,
_PDC will not be used in ARM platform, so make Make _PDC only for
platforms with Intel CPUs.

Introduce ARCH_MIGHT_HAVE_ACPI_PDC and move _PDC related code in
ACPI processor driver into a single file processor_pdc.c, make x86
and ia64 select it when ACPI is enabled.

This patch also use pr_* to replace printk to fix the checkpatch
warning and factor acpi_processor_alloc_pdc() a little bit to
avoid duplicate pr_err() code.

Suggested-by: Robert Richter <rric@kernel.org>
Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 2f3abcf..44a6915 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -10,6 +10,7 @@
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select PCI if (!IA64_HP_SIM)
 	select ACPI if (!IA64_HP_SIM)
+	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
 	select PM if (!IA64_HP_SIM)
 	select HAVE_UNSTABLE_SCHED_CLOCK
 	select HAVE_IDE