x86/apic: Add separate apic_id_valid() functions for selected apic drivers

As suggested by Suresh Siddha and Yinghai Lu:

For x2apic pre-enabled systems, apic driver is set already early
through early_acpi_boot_init()/early_acpi_process_madt()/
acpi_parse_madt()/default_acpi_madt_oem_check() path so that
apic_id_valid() checking will be sufficient during MADT and SRAT
parsing.

For non-x2apic pre-enabled systems, all apic ids should be less
than 255.

This allows us to substitute the checks in
arch/x86/kernel/acpi/boot.c::acpi_parse_x2apic() and
arch/x86/mm/srat.c::acpi_numa_x2apic_affinity_init() with
apic->apic_id_valid().

In addition we can avoid feigning the x2apic cpu feature in the
NumaChip apic code.

The following apic drivers have separate apic_id_valid()
functions which will accept x2apic type IDs :

 x2apic_phys
 x2apic_cluster
 x2apic_uv_x
 apic_numachip

Signed-off-by: Steffen Persvold <sp@numascale.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Daniel J Blueman <daniel@numascale-asia.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Jack Steiner <steiner@sgi.com>
Link: http://lkml.kernel.org/r/1331925935-13372-1-git-send-email-sp@numascale.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index a9371c9..d3eaac4 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h
@@ -535,7 +535,7 @@
 
 static inline int default_apic_id_valid(int apicid)
 {
-	return x2apic_mode || (apicid < 255);
+	return (apicid < 255);
 }
 
 extern void default_setup_apic_routing(void);
diff --git a/arch/x86/include/asm/x2apic.h b/arch/x86/include/asm/x2apic.h
index 6bf5b8e..92e54ab 100644
--- a/arch/x86/include/asm/x2apic.h
+++ b/arch/x86/include/asm/x2apic.h
@@ -18,6 +18,11 @@
 	return cpu_online_mask;
 }
 
+static int x2apic_apic_id_valid(int apicid)
+{
+	return 1;
+}
+
 static int x2apic_apic_id_registered(void)
 {
 	return 1;