x86, x2apic: Simplify apic init in SMP and UP builds

Move enable_IR_x2apic() inside the default_setup_apic_routing(),
and for SMP platforms, move the default_setup_apic_routing() after
smp_sanity_check(). This cleans up the code that tries to avoid multiple
calls to default_setup_apic_routing() when smp_sanity_check() fails (which
goes through the APIC_init_uniprocessor() path).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <20100827181049.173087246@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/apic/apic.c

@@ -1665,10 +1665,7 @@ int __init APIC_init_uniprocessor(void)
 	}
 #endif
 
-#ifndef CONFIG_SMP
-	enable_IR_x2apic();
 	default_setup_apic_routing();
-#endif
 
 	verify_local_APIC();
 	connect_bsp_APIC();