btrfs: fix backport of 2175bf57dc952 in 5.10.13

btrfs: fix backport of 2175bf57dc952 in 5.10.13

There's a mistake in backport of upstream commit 2175bf57dc95 ("btrfs:
fix possible free space tree corruption with online conversion") as
5.10.13 commit 2175bf57dc95.

The enum value BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED has been added to the
wrong enum set, colliding with value of BTRFS_FS_QUOTA_ENABLE. This
could cause problems during the tree conversion, where the quotas
wouldn't be set up properly but the related code executed anyway due to
the bit set.

Link: https://lore.kernel.org/linux-btrfs/20210219111741.95DD.409509F4@e16-tech.com
Reported-by: Wang Yugui <wangyugui@e16-tech.com>
CC: stable@vger.kernel.org # 5.10.13+
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>