WorkQueue: Fix up arch-specific work items where possible

Fix up arch-specific work items where possible to use the new work_struct and
delayed_work structs.

Three places that enqueue bits of their stack and then return have been marked
with #error as this is not permitted.

Signed-Off-By: David Howells <dhowells@redhat.com>
diff --git a/arch/um/drivers/port_kern.c b/arch/um/drivers/port_kern.c
index ce9f373..6dfe632 100644
--- a/arch/um/drivers/port_kern.c
+++ b/arch/um/drivers/port_kern.c
@@ -132,7 +132,7 @@
 DECLARE_MUTEX(ports_sem);
 struct list_head ports = LIST_HEAD_INIT(ports);
 
-void port_work_proc(void *unused)
+void port_work_proc(struct work_struct *unused)
 {
 	struct port_list *port;
 	struct list_head *ele;
@@ -150,7 +150,7 @@
 	local_irq_restore(flags);
 }
 
-DECLARE_WORK(port_work, port_work_proc, NULL);
+DECLARE_WORK(port_work, port_work_proc);
 
 static irqreturn_t port_interrupt(int irq, void *data)
 {