[S390] use LIST_HEAD instead of LIST_HEAD_INIT

single list_head variable initialized with LIST_HEAD_INIT could almost
always can be replaced with LIST_HEAD declaration, this shrinks the code
and looks better.

Signed-off-by: Denis Cheng <crquan@gmail.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c
index 394980b..880b0eb 100644
--- a/arch/s390/mm/extmem.c
+++ b/arch/s390/mm/extmem.c
@@ -83,7 +83,7 @@
 };
 
 static DEFINE_MUTEX(dcss_lock);
-static struct list_head dcss_list = LIST_HEAD_INIT(dcss_list);
+static LIST_HEAD(dcss_list);
 static char *segtype_string[] = { "SW", "EW", "SR", "ER", "SN", "EN", "SC",
 					"EW/EN-MIXED" };