s390/vdso: fix vdso data page definition

The vdso data page actually contains an array. Fix that.
This doesn't fix a real bug, just reflects reality.
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/vdso.c

@@ -87,10 +87,10 @@ __setup("vdso=", vdso_setup);
  * The vdso data page
  */
 static union {
-	struct vdso_data	data;
+	struct vdso_data	data[CS_BASES];
 	u8			page[PAGE_SIZE];
 } vdso_data_store __page_aligned_data;
-struct vdso_data *vdso_data = (struct vdso_data *)&vdso_data_store.data;
+struct vdso_data *vdso_data = vdso_data_store.data;
 
 void vdso_getcpu_init(void)
 {