x86: split safe_smp_processor_id

This implementation in x86_64 is clean and consistent, but we
sacrifice it for the sake of being equal to i386 (since the other
way around would be harder).
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/asm-x86/smp_64.h

@@ -27,12 +27,12 @@ static inline int num_booting_cpus(void)
 	return cpus_weight(cpu_callout_map);
 }
 
+#define safe_smp_processor_id()		smp_processor_id()
 #else /* CONFIG_SMP */
 #define stack_smp_processor_id() 0
-
+#define safe_smp_processor_id() 0
 #endif /* !CONFIG_SMP */
 
-#define safe_smp_processor_id()		smp_processor_id()
 
 #endif