linux-phytec-ti

btrfs: Remove unused sysfs code

Removes code no longer used. The sysfs file itself is kept, because the
btrfs developers expressed interest in putting new entries to sysfs.

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>