[S390] smp: setup smp_processor_id early

smp_processor_id() is supposed to work before setup_arch() gets called.
Before that smp_processor_id() may return just an arbitrary value that
is contained in the uninitialized boot lowcore.
So provide the arch function which will override the weak function in
init/main.c.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/setup.c

@@ -849,7 +849,6 @@ setup_arch(char **cmdline_p)
 	setup_lowcore();
 
         cpu_init();
-	__cpu_logical_map[0] = stap();
 	s390_init_cpu_topology();
 
 	/*

arch/s390/kernel/smp.c

@@ -717,6 +717,12 @@ void __init smp_cpus_done(unsigned int max_cpus)
 {
 }
 
+void __init smp_setup_processor_id(void)
+{
+	S390_lowcore.cpu_nr = 0;
+	__cpu_logical_map[0] = stap();
+}
+
 /*
  * the frequency of the profiling timer can be changed
  * by writing a multiplier value into /proc/profile.