btrfs: make clear_extent_buffer_uptodate return void

Does not return any errors, nor anything from the callgraph.

Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 013af05..ad1d28c 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -331,7 +331,7 @@
 void clear_extent_buffer_dirty(struct extent_buffer *eb);
 int set_extent_buffer_dirty(struct extent_buffer *eb);
 void set_extent_buffer_uptodate(struct extent_buffer *eb);
-int clear_extent_buffer_uptodate(struct extent_buffer *eb);
+void clear_extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_uptodate(struct extent_buffer *eb);
 int extent_buffer_under_io(struct extent_buffer *eb);
 int map_private_extent_buffer(struct extent_buffer *eb, unsigned long offset,