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>

include/linux/netpoll.h

@@ -32,7 +32,7 @@ struct netpoll_info {
 	struct netpoll *rx_np; /* netpoll that registered an rx_hook */
 	struct sk_buff_head arp_tx; /* list of arp requests to reply to */
 	struct sk_buff_head txq;
-	struct work_struct tx_work;
+	struct delayed_work tx_work;
 };
 
 void netpoll_poll(struct netpoll *np);