btrfs: tracepoints: remove no longer used tracepoints for eb locking

btrfs: tracepoints: remove no longer used tracepoints for eb locking

There are several tracepoints for extent buffer locks that are not used
anymore:

  * btrfs_tree_read_unlock_blocking
  * btrfs_set_lock_blocking_read
  * btrfs_set_lock_blocking_write
  * btrfs_tree_read_lock_atomic

These stopped being used after we switched extent buffer locks from a
custom implementation to rw semaphores in commit 196d59ab9ccc
("btrfs: switch extent buffer tree lock to rw_semaphore").

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