[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>

arch/s390/kernel/swsusp_asm64.S

@@ -256,6 +256,9 @@ restore_registers:
 	lghi	%r2,0
 	brasl	%r14,arch_set_page_states
 
+	/* Reinitialize the channel subsystem */
+	brasl	%r14,channel_subsystem_reinit
+
 	/* Return 0 */
 	lmg	%r6,%r15,STACK_FRAME_OVERHEAD + __SF_GPRS(%r15)
 	lghi	%r2,0

drivers/s390/cio/css.c

@@ -1043,6 +1043,11 @@ static int __init channel_subsystem_init_sync(void)
 }
 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)