evl/poll: lockdep: delete group mutex at release

With dynamic lock classes enabled for mutexes, we have to destroy the
latter thoroughly after usage so that classes are removed. Otherwise,
lockdep may complain loudly about registering classes twice.

Signed-off-by: Philippe Gerum <[email protected]>

Author: pgerum

kernel/evl/poll.c

@@ -653,6 +653,7 @@ static int poll_release(struct inode *inode, struct file *filp)
 	evl_schedule();
 
 	flush_items(group);
+	evl_destroy_kmutex(&group->item_lock);
 	evl_release_file(&group->efile);
 	kfree(group);