edac: use to_delayed_work()

The edac-core driver includes code which assumes that the work_struct
which is included in every delayed_work is the first member of that
structure. This is currently the case but might change in the future, so
use to_delayed_work() instead, which doesn't make such an assumption.

linux-2.6.30-rc1 has the to_delayed_work() function that will allow this
patch to work

Signed-off-by: Jean Delvare <[e-mail]>
Signed-off-by: Doug Thompson <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/edac/edac_device.c

···
  */
 static void edac_device_workq_function(struct work_struct *work_req)
 {
-	struct delayed_work *d_work = (struct delayed_work *)work_req;
+	struct delayed_work *d_work = to_delayed_work(work_req);
 	struct edac_device_ctl_info *edac_dev = to_edac_device_ctl_work(d_work);
 
 	mutex_lock(&device_ctls_mutex);

drivers/edac/edac_mc.c

···
  */
 static void edac_mc_workq_function(struct work_struct *work_req)
 {
-	struct delayed_work *d_work = (struct delayed_work *)work_req;
+	struct delayed_work *d_work = to_delayed_work(work_req);
 	struct mem_ctl_info *mci = to_edac_mem_ctl_work(d_work);
 
 	mutex_lock(&mem_ctls_mutex);

drivers/edac/edac_pci.c

···
  */
 static void edac_pci_workq_function(struct work_struct *work_req)
 {
-	struct delayed_work *d_work = (struct delayed_work *)work_req;
+	struct delayed_work *d_work = to_delayed_work(work_req);
 	struct edac_pci_ctl_info *pci = to_edac_pci_ctl_work(d_work);
 	int msec;
 	unsigned long delay;