acer-wmi: remove debugfs entries upon unloading

The exit function neglects to remove debugfs entries, leading to a BUG
on reload.

[akpm@linux-foundation.org: cleanups]
Signed-off-by: Russ Dill <Russ.Dill@gmail.com>
Acked-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/acer-wmi.c

@@ -1272,6 +1272,7 @@ static int __init acer_wmi_init(void)
 static void __exit acer_wmi_exit(void)
 {
 	remove_sysfs(acer_platform_device);
+	remove_debugfs();
 	platform_device_del(acer_platform_device);
 	platform_driver_unregister(&acer_platform_driver);