x86: refactor ->check_phys_apicid_present() subarch methods

- spread out the namespace to per driver methods

 - extend it to 64-bit as well so that we can use
   apic->check_phys_apicid_present() unconditionally

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/genx2apic_cluster.c b/arch/x86/kernel/genx2apic_cluster.c
index 710d612..7062e24 100644
--- a/arch/x86/kernel/genx2apic_cluster.c
+++ b/arch/x86/kernel/genx2apic_cluster.c
@@ -202,7 +202,7 @@
 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 	.apicid_to_cpu_present		= NULL,
 	.setup_portio_remap		= NULL,
-	.check_phys_apicid_present	= NULL,
+	.check_phys_apicid_present	= default_check_phys_apicid_present,
 	.enable_apic_mode		= NULL,
 	.phys_pkg_id			= phys_pkg_id,
 	.mps_oem_check			= NULL,