[S390] extmem unbalanced spin_lock.

segment save will exit with a lock held if the passed segment doesn't
exist. Any subsequent call to segment_save will lead to a deadlock.
Fix this and give up the lock before returning.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/extmem.c

@@ -563,8 +563,9 @@ segment_save(char *name)
 	seg = segment_by_name (name);
 
 	if (seg == NULL) {
-		PRINT_ERR ("could not find segment %s in segment_save, please report to linux390@de.ibm.com\n",name);
-		return;
+		PRINT_ERR("could not find segment %s in segment_save, please "
+			  "report to linux390@de.ibm.com\n", name);
+		goto out;
 	}
 
 	startpfn = seg->start_addr >> PAGE_SHIFT;