WorkStruct: Separate delayable and non-delayable events.

Separate delayable work items from non-delayable work items be splitting them
into a separate structure (delayed_work), which incorporates a work_struct and
the timer_list removed from work_struct.

The work_struct struct is huge, and this limits it's usefulness.  On a 64-bit
architecture it's nearly 100 bytes in size.  This reduces that by half for the
non-delayable type of event.

Signed-Off-By: David Howells <dhowells@redhat.com>

include/linux/kbd_kern.h

@@ -158,7 +158,7 @@ static inline void con_schedule_flip(struct tty_struct *t)
 	if (t->buf.tail != NULL)
 		t->buf.tail->commit = t->buf.tail->used;
 	spin_unlock_irqrestore(&t->buf.lock, flags);
-	schedule_work(&t->buf.work);
+	schedule_delayed_work(&t->buf.work, 0);
 }
 
 #endif