btrfs: enhance extent_io_tree error reports

Pass the type of the extent io tree operation which failed in the report
helper. The message wording and contents is updated, though locking
might be the cause of the error it's probably not the only one and we're
interested in the state.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>