ext4: drop all delonly descriptions

When counting reserved clusters, delayed type is always equal to delonly
type now, hence drop all delonly descriptions in parameters and
comments.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240813123452.2824659-13-yi.zhang@huaweicloud.com


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