ocfs2: remove redundant assignment to pointer root_bh

ocfs2: remove redundant assignment to pointer root_bh

The variable 'root_bh' is being initialized with a value that is not
read, it is being re-assigned later on closer to its use.  The early
initialization is redundant and can be removed.

Link: https://lkml.kernel.org/r/20211228013719.620923-1-colin.i.king@gmail.com
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>