[S390] add hook to reenable mss after hibernation

Reenable multiple subchannel sets after hibernation,
prior to the device callbacks.

Cc: <stable@kernel.org>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 19635d4..5116491 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -1043,6 +1043,11 @@
 }
 subsys_initcall_sync(channel_subsystem_init_sync);
 
+void channel_subsystem_reinit(void)
+{
+	chsc_enable_facility(CHSC_SDA_OC_MSS);
+}
+
 #ifdef CONFIG_PROC_FS
 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)