jbd2: fix incorrect code style

Remove unnecessary blank.

Signed-off-by: Xianting Tian <xianting_tian@126.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/1595077057-8048-1-git-send-email-xianting_tian@126.com


Signed-off-by: Theodore Ts'o <tytso@mit.edu>