[S390] hibernate: directly trigger subchannel evaluation

Using the generic css_schedule_eval to evaluate subchannels
while resuming from hibernation is very slow when used with
many devices. Provide a new evaluation trigger which exploits
css_sched_sch_todo and use this in the resume callback for
ccw devices.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/cio/cio.h

@@ -68,8 +68,13 @@ struct schib {
 	__u8 mda[4];		 /* model dependent area */
 } __attribute__ ((packed,aligned(4)));
 
+/*
+ * When rescheduled, todo's with higher values will overwrite those
+ * with lower values.
+ */
 enum sch_todo {
 	SCH_TODO_NOTHING,
+	SCH_TODO_EVAL,
 	SCH_TODO_UNREG,
 };