x86: clean up apic->apic_id_registered() methods

Impact: cleanup

x86 subarchitectures each defined a "apic_id_registered()" method,
which could be an inline function depending on which subarch we build
for, and which was also the name of a genapic field.

Untangle this namespace spaghetti by giving each of the instances
a separate name.

Also remove wrapper macro obfuscation.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/mach-default/mach_apic.h b/arch/x86/include/asm/mach-default/mach_apic.h
index 2448b92..6a454fa 100644
--- a/arch/x86/include/asm/mach-default/mach_apic.h
+++ b/arch/x86/include/asm/mach-default/mach_apic.h
@@ -25,7 +25,6 @@
 #define INT_DELIVERY_MODE (apic->int_delivery_mode)
 #define INT_DEST_MODE (apic->int_dest_mode)
 #define TARGET_CPUS	  (apic->target_cpus())
-#define apic_id_registered (apic->apic_id_registered)
 #define init_apic_ldr (apic->init_apic_ldr)
 #define cpu_mask_to_apicid (apic->cpu_mask_to_apicid)
 #define cpu_mask_to_apicid_and (apic->cpu_mask_to_apicid_and)
@@ -57,7 +56,7 @@
 	apic_write(APIC_LDR, val);
 }
 
-static inline int apic_id_registered(void)
+static inline int default_apic_id_registered(void)
 {
 	return physid_isset(read_apic_id(), phys_cpu_present_map);
 }