ha_innobase::prepare_inplace_alter_table(): Remove always-true conditions.
Near the start of the function, we would already have returned if
no ALTER TABLE operation flags were set that would require special
action from InnoDB.

It turns out that the conditions were redundant already when they were
introduced in mysql/mysql-server@241387a2b6b61fb8a4f78dc4ad0aaa289400c694
and in commit 068c6197.

Thanks to Nikita Malyavin for noticing this.