xen/dev: remove __unused from driver argument of identify functions

The driver argument is most certainly now used by these functions.  When
originally implemented it might have been unused, but not now.

Reviewed by: royger

sys/dev/xen/balloon/balloon.c

@@ -334,7 +334,7 @@ watch_target(struct xs_watch *watch,
  * \param parent  The NewBus parent device for any devices this method adds.
  */
 static void
-xenballoon_identify(driver_t *driver __unused, device_t parent)
+xenballoon_identify(driver_t *driver, device_t parent)
 {
 	/*
 	 * A single device instance for our driver is always present

sys/dev/xen/control/control.c

@@ -401,7 +401,7 @@ xctrl_on_watch_event(struct xs_watch *watch, const char **vec, unsigned int len)
  * \param parent  The NewBus parent device for any devices this method adds.
  */
 static void
-xctrl_identify(driver_t *driver __unused, device_t parent)
+xctrl_identify(driver_t *driver, device_t parent)
 {
 	/*
 	 * A single device instance for our driver is always present

sys/dev/xen/grant_table/grant_table.c

@@ -569,7 +569,7 @@ MTX_SYSINIT(gnttab, &gnttab_list_lock, "GNTTAB LOCK", MTX_DEF | MTX_RECURSE);
  * \param parent  The NewBus parent device for any devices this method adds.
  */
 static void
-granttable_identify(driver_t *driver __unused, device_t parent)
+granttable_identify(driver_t *driver, device_t parent)
 {
 
 	KASSERT(xen_domain(),

sys/dev/xen/xenstore/xenstore_dev.c

@@ -474,7 +474,7 @@ static struct cdevsw xs_dev_cdevsw = {
  * \param parent  The NewBus parent device for any devices this method adds.
  */
 static void
-xs_dev_identify(driver_t *driver __unused, device_t parent)
+xs_dev_identify(driver_t *driver, device_t parent)
 {
 	/*
 	 * A single device instance for our driver is always present

sys/dev/xen/xenstore/xenstored_dev.c

@@ -95,7 +95,7 @@ xsd_dev_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr,
  * \param parent  The NewBus parent device for any devices this method adds.
  */
 static void
-xsd_dev_identify(driver_t *driver __unused, device_t parent)
+xsd_dev_identify(driver_t *driver, device_t parent)
 {
 
 	if (!xen_domain() || xs_initialized())

sys/xen/xenbus/xenbusb.c

@@ -622,7 +622,7 @@ xenbusb_nop_confighook_cb(void *arg __unused)
 /*--------------------------- Public Functions -------------------------------*/
 /*--------- API comments for these methods can be found in xenbusb.h ---------*/
 void
-xenbusb_identify(driver_t *driver __unused, device_t parent)
+xenbusb_identify(driver_t *driver, device_t parent)
 {
 	/*
 	 * A single instance of each bus type for which we have a driver