ext4: don't show commit interval if it is zero

If commit interval is 0, it means using default value.

Fixes: 6e47a3cc ("ext4: get rid of super block and sbi from handle_mount_ops()")
Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Link: https://lore.kernel.org/r/20221219015128.876717-1-wangjianjian3@huawei.com


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