staging: ozwpan: use tasklet_kill in device remove/release process

Some driver uses tasklet_disable in device remove/release process,
tasklet_disable will inc tasklet->count and return. If the tasklet
is not handled yet under some softirq pressure, the tasklet will be
placed on the tasklet_vec, never have a chance to be excuted. This might
lead to a heavy loaded ksoftirqd, wakeup with pending_softirq, but
tasklet is disabled. tasklet_kill should be used in this case.

Signed-off-by: Xiaotian Feng <dannyfeng@tencent.com>
Cc: Rupesh Gujare <rgujare@ozmodevices.com>
Cc: Chris Kelly <ckelly@ozmodevices.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ozwpan/ozhcd.c

@@ -2304,8 +2304,8 @@ int oz_hcd_init(void)
  */
 void oz_hcd_term(void)
 {
-	tasklet_disable(&g_urb_process_tasklet);
-	tasklet_disable(&g_urb_cancel_tasklet);
+	tasklet_kill(&g_urb_process_tasklet);
+	tasklet_kill(&g_urb_cancel_tasklet);
 	platform_device_unregister(g_plat_dev);
 	platform_driver_unregister(&g_oz_plat_drv);
 	oz_trace("Pending urbs:%d\n", atomic_read(&g_pending_urbs));