[PATCH] Fix SAK_work workqueue initialization.

Somewhere in the rewrite of the work queues my cleanup of SAK handling
got broken.  Maybe I didn't retest it properly or possibly the API
was changing so fast I missed something.  Regardless currently
triggering a SAK now generates an ugly BUG_ON and kills the kernel.

Thanks to Alexey Dobriyan <adobriyan@openvz.org> for spotting this.

This modifies the use of SAK_work to initialize it when the data
structure it resides in is initialized, and to simply call
schedule_work when we need to generate a SAK.  I update both
data structures that have a SAK_work member for consistency.

All of the old PREPARE_WORK calls that are now gone.

If we call schedule_work again before it has processed it
has generated the first SAK it will simply ignore the duplicate
schedule_work request.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/sysrq.c

@@ -89,7 +89,6 @@ static struct sysrq_key_op sysrq_loglevel_op = {
 static void sysrq_handle_SAK(int key, struct tty_struct *tty)
 {
 	struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
-	PREPARE_WORK(SAK_work, vc_SAK);
 	schedule_work(SAK_work);
 }
 static struct sysrq_key_op sysrq_SAK_op = {