btrfs: stop searching for EXTENT_DIRTY bit in the excluded extents io tree

btrfs: stop searching for EXTENT_DIRTY bit in the excluded extents io tree

At btrfs_add_new_free_space() we keep searching for ranges in the excluded
extents io tree that have the EXTENT_DIRTY bit set, however we never ever
set that bit for ranges in that tree. That is a leftover from when that
function used the global freed extents trees (fs_info->freed_extents[2]),
where we used both the EXTENT_DIRTY and EXTENT_UPTODATE bits, but those
trees are gone with commit fe119a6eeb67 ("btrfs: switch to per-transaction
pinned extents"), which introduced the fs_info->excluded_extents io tree,
where only EXTENT_UPTODATE is set.

So remove the EXTENT_DIRTY bit search at btrfs_add_new_free_space().

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>