[S390] New get_cpu_id() inline assembly

Replace two stidp inline assemblies with one global implementation.

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 50c5210..49567d8 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -106,7 +106,7 @@
         /*
          * Store processor id in lowcore (used e.g. in timer_interrupt)
          */
-	asm volatile("stidp %0": "=m" (S390_lowcore.cpu_data.cpu_id));
+	get_cpu_id(&S390_lowcore.cpu_data.cpu_id);
         S390_lowcore.cpu_data.cpu_addr = addr;
 
         /*