btrfs: force free space tree for bs > ps cases

btrfs: force free space tree for bs > ps cases

[BUG]
Currently we only enforcing the free space tree for bs < ps cases, but
with the recently added bs > ps support, we lack the free space tree
enforcing, causing explicit v1 cache mount option to fail on bs > ps
cases:

  # mount -o space_cache=v1 /dev/test/scratch1  /mnt/btrfs/
  mount: /mnt/btrfs: wrong fs type, bad option, bad superblock on /dev/mapper/test-scratch1, missing codepage or helper program, or other error.
         dmesg(1) may have more information after failed mount system call.

  # dmesg -t | tail -n7
  BTRFS: device fsid ac14a6fa-4ec9-449e-aec9-7d1777bfdc06 devid 1 transid 11 /dev/mapper/test-scratch1 (253:3) scanned by mount (2849)
  BTRFS info (device dm-3): first mount of filesystem ac14a6fa-4ec9-449e-aec9-7d1777bfdc06
  BTRFS info (device dm-3): using crc32c checksum algorithm
  BTRFS warning (device dm-3): support for block size 8192 with page size 4096 is experimental, some features may be missing
  BTRFS warning (device dm-3): space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2
  BTRFS warning (device dm-3): v1 space cache is not supported for page size 4096 with sectorsize 8192
  BTRFS error (device dm-3): open_ctree failed: -22

[FIX]
Just enable the same free space tree for bs > ps cases, aligning the
behavior to bs < ps cases.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>