workqueue: Use "@..." in function comment to describe variable length argument

Previously, it was using "remaining args" without leading "@" which isn't
valid. Let's follow snprintf()'s example and use "@...".
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>

include/linux/workqueue.h

@@ -473,7 +473,7 @@ void workqueue_softirq_dead(unsigned int cpu);
  * @fmt: printf format for the name of the workqueue
  * @flags: WQ_* flags
  * @max_active: max in-flight work items, 0 for default
- * remaining args: args for @fmt
+ * @...: args for @fmt
  *
  * For a per-cpu workqueue, @max_active limits the number of in-flight work
  * items for each CPU. e.g. @max_active of 1 indicates that each CPU can be