[S390] bss section clearing.

Clear only memory from __bss_start to __bss_stop when clearing the bss
section. Not until _end, which currently happens to be the same.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 5d02e48..afca1c6 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -110,7 +110,7 @@
  */
 static noinline __init void clear_bss_section(void)
 {
-	memset(__bss_start, 0, _end - __bss_start);
+	memset(__bss_start, 0, __bss_stop - __bss_start);
 }
 
 /*